309 results on '"Leandro Vargas"'
Search Results
102. Vigilância popular ambiental e siderurgia: as experiências de Piquiá de Baixo (MA) e Santa Cruz (RJ), Brasil
- Author
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Carvalho, Leandro Vargas Barreto de, primary, Rocha, Flávio, additional, and Finamore, Renan, additional
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- 2021
- Full Text
- View/download PDF
103. Yield, germination and herbicide residue in seeds of preharvest desiccated wheat
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Lais Tessari Perboni, Joanei Cechin, Leandro Vargas, Humberto De Souza Farias, Renan Ricardo Zandoná, Dirceu Agostinetto, LAIS TESSARI PERBONI, DIRCEU AGOSTINETTO, LEANDRO VARGAS, CNPT, JOANEI CECHIN, RENAN RICARDO ZANDONÁ, and HUMBERTO DE SOUZA FARIAS.
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0106 biological sciences ,Triticum aestivum ,Trigo ,lcsh:Plant culture ,Biology ,01 natural sciences ,chemistry.chemical_compound ,Paraquat ,herbicide ,Yield (wine) ,herbicida ,lcsh:SB1-1110 ,harvest aid ,Residue (complex analysis) ,Herbicides ,fungi ,food and beverages ,04 agricultural and veterinary sciences ,antecipação da colheita ,Horticulture ,physiological quality ,chemistry ,Glufosinate ,Germination ,Glyphosate ,Wheat ,040103 agronomy & agriculture ,0401 agriculture, forestry, and fisheries ,Preharvest ,qualidade fisiológica ,Desiccation ,Agronomy and Crop Science ,010606 plant biology & botany - Abstract
The goals of this study were to evaluate herbicide application rates at different timings for preharvest desiccation of wheat (Trial 1), as well as to evaluate the effect of the timing of herbicide desiccation at preharvest and harvest timing (Trial 2) on yield, germination, and herbicide residue in wheat seed. In Trial 1, treatments consisted of two application rates of glufosinate, glyphosate, paraquat, or paraquat+diuron and a control without application; application time periods were in the milk grain to early dough stage, soft dough to hard dough stage, and hard dough stage. In Trial 2, treatments consisted of different application time periods (milk grain to early dough stage, and soft dough to hard dough stage), different herbicides (glufosinate, 2,4-D+glyphosate, and untreated control), and different harvest times (5, 10 and 15 days after herbicide application). One thousand seeds weight, yield, first and final germination count, and herbicide residue on seeds were evaluated. Preharvest desiccation with paraquat, glufosinate, and 2,4-D+glyphosate at the milk grain to early dough stage reduces wheat yield. Regardless of the herbicide and application rate, application in the milk grain to early dough stage and soft dough to hard dough stage provides greater germination of wheat seeds, except at the lower dose of paraquat. Systemic herbicides accumulate more in wheat seeds. Resumo: Os objetivos foram avaliar doses de herbicidas em diferentes épocas de dessecação pré-colheita do trigo (Experimento 1); e, o efeito de herbicidas em diferentes épocas de dessecação pré-colheita e épocas de colheita (Experimento 2) sobre a produtividade, germinação e resíduos de herbicidas em sementes de trigo. No experimento 1, os tratamentos foram: duas doses e testemunha sem aplicação dos herbicidas glufosinate, glyphosate, paraquat, paraquat+diuron; e, as épocas de aplicação foram: grão leitoso a pastoso, grão pastoso a farináceo e grão farináceo duro. No experimento 2, os tratamentos foram as épocas de aplicação: grão leitoso a pastoso e grão pastoso a farináceo; os herbicidas: glufosinate, 2,4-D+glyphosate e testemunha sem aplicação; e, as épocas de colheitas: 5, 10 e 15 dias após aplicação. Avaliaram-se massa de mil sementes, produtividade, primeira e contagem final da germinação e resíduo dos herbicidas nas sementes. A dessecação pré-colheita com paraquat, glufosinate e 2,4-D+glyphosate em estádio de grão leitoso a pastoso reduz a produtividade do trigo. Independente do herbicida e dose, aplicação em estádio de grão leitoso a pastoso e grão pastoso a farináceo proporciona maior germinação de sementes de trigo, exceto a menor dose de paraquat. Herbicidas sistêmicos acumulam-se mais nas sementes de trigo.
- Published
- 2018
104. Physiological Performance of Seeds and Level of Herbicide Residues Depending on Application of 2.4-D in Wheat
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Nixon da Rosa Westendorff, Ana Claudia Langaro, Leandro Vargas, G.R. Aisenberg, Dirceu Agostinetto, and LEANDRO VARGAS, CNPT.
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Physiology ,QH301-705.5 ,Triticum aestivum ,Trigo ,Plant Science ,Biology ,01 natural sciences ,Biochemistry ,Crop ,Erva Daninha ,weeds ,Dry matter ,Biology (General) ,Residue (complex analysis) ,010401 analytical chemistry ,germinação ,Botany ,food and beverages ,04 agricultural and veterinary sciences ,0104 chemical sciences ,Horticulture ,plantas daninhas ,germination ,Germination ,QK1-989 ,Wheat ,040103 agronomy & agriculture ,dry matter ,0401 agriculture, forestry, and fisheries ,matéria seca ,Winter season ,Agronomy and Crop Science - Abstract
Horseweed control through application of 2.4-D in the winter season is an alternative to manage biotypes resistant to herbicides that belong to other mechanisms of action. The objectives of this study were to assess the physiological quality of wheat seeds and determine the rate of 2.4-D residue, as function of application stages and herbicide rates. The treatments were arranged in factorial scheme, with three application stages (flowering, soft dough and hard dough), and four 2.4-D rates (0; 504; 1,008 and 2,015 g a.i. ha-1). The application of 2.4-D in the wheat crop changed physiological seed quality by increased the rate and total percentage of germination. The application of 2.4-D resulted in herbicide accumulation in seeds, especially when application was carried out at the soft dough stage. Also, the increase in herbicide rate increased the level of residue in the seeds. However, regardless of stage of application for 2.4-D and herbicide rate in use, the values of residue found in the seeds were below the allowed maximum limit. RESUMO: O controle de buva através da aplicação de 2,4-D na estação hibernal de cultivo é alternativa para o manejo de biótipos com resistência a herbicidas pertencentes a outros mecanismos de ação. Os objetivos do estudo foram avaliar a qualidade fisiológica das sementes de trigo e determinar o resíduo de 2,4-D, em função do estádio de aplicação e de doses do herbicida. Os tratamentos foram arranjados em esquema fatorial, sendo três estádios de aplicação (florescimento, grão pastoso e massa firme) e quatro doses do herbicida 2,4-D (0, 504, 1.008 e 2.015 g i.a. ha-1). A aplicação de 2,4-D na cultura do trigo alterou a qualidade fisiológica das sementes, resultando em aumento da velocidade e da porcentagem total de germinação. A aplicação do 2,4-D resultou em acúmulo de resíduo do herbicida nas sementes, principalmente quando a aplicação foi feita no estádio de grão pastoso, e o aumento da dose herbicida elevou a concentração de resíduo. Contudo, independentemente da época em que o 2,4-D foi aplicado, assim como da dose utilizada, os valores de resíduo observados nas sementes encontraram-se abaixo do limite máximo permitido.
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- 2018
105. Development stages horseweed in soybeans competition
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Leandro Vargas, Diecson Ruy Orsolin da Silva, Dirceu Agostinetto, DIECSON RUY ORSOLIN DA SILVA, UFSM, DIRCEU AGOSTINETTO, UFPEL, and LEANDRO VARGAS, CNPT.
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Soja ,Glycine max ,Agriculture (General) ,Planta daninha ,media_common.quotation_subject ,Greenhouse ,Biology ,série de substituição ,Competition (biology) ,Intraspecific competition ,S1-972 ,Rosette (botany) ,Buva ,Dry matter ,media_common ,fungi ,food and beverages ,General Medicine ,Plant population ,Weed control ,Agronomy ,competitivity ,Shoot ,Conyza bonariensis ,replacement series ,competitividade ,Soybean - Abstract
The objective of this study was to evaluate the relative competitive ability of soybean with different development stages of hairy fleabane. Two experiments were conducted in greenhouse, in a completely randomized design. In the experiment it was tested soybean and hairy fleabane competition at different stage of development (rosette and 15 cm height) at the proportions 100:0, 75:25, 50:50, 25:75 and 0:100, and total plant population was 315 plant m-2. The variables evaluated were plant height, leaf area, and shoot dry matter (leaves and stems). Competitive analysis was performed by diagrams and interpreting the competitiveness index. The soybean has greater competitive ability that horseweed for both development stages. The intraspecific competition is more intense for soybean when in hairy fleabane rosette stage, and the competitive relations are equivalent between soybean and hairy fleabane of 15 cm tall. The both hairy fleabane stages were injured in the soybeans competition.
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- 2018
106. Photosynthetic Performance of Glyphosate Resistant and Glyphosate Susceptible Hairy Fleabane under Light Intensity
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Diecson Ruy Orsolin da Silva, Filipe Martins Santos, Leandro Vargas, Dirceu Agostinetto, DIECSON RUY ORSOLIN DA SILVA, UFSM, LEANDRO VARGAS, CNPT, and DIRCEU AGOSTINETTO, UFPEL.
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ecological adaptability ,0106 biological sciences ,Stomatal conductance ,QH301-705.5 ,fluxo de fótons fotossintéticos ,Physiology ,gas exchange ,Plant Science ,Biology ,photosynthetic photon flux ,Photosynthesis ,01 natural sciences ,Biochemistry ,chemistry.chemical_compound ,Buva ,Biology (General) ,Water-use efficiency ,adaptabilidade ecológica ,Transpiration ,troca de gases ,taxa de assimilação de carbono ,Botany ,carbon assimilation rate ,04 agricultural and veterinary sciences ,Weed control ,Light intensity ,Horticulture ,light response curve ,chemistry ,Compensation point ,QK1-989 ,curva-resposta de luz ,Glyphosate ,Conyza bonariensis ,040103 agronomy & agriculture ,0401 agriculture, forestry, and fisheries ,Agronomy and Crop Science ,010606 plant biology & botany - Abstract
Herbicide resistance can confer lower competitive abilities; however scarse information is available about the photosynthetic performance between glyphosate-resistant and -susceptible hairy fleabane biotypes coming from areas with similar weed management history. Thus, the goal was to evaluate the photosynthetic performance under different light intensities between glyphosate-resistant and -susceptible hairy fleabane biotypes, from RR soybean fields with a similar weed management history. The tested factors were glyphosate resistant and susceptible biotypes and 12 levels of photosynthetic photon flux density. Plants were cultivated in plastic cups, and at the stage of 10-12 leaves they were subjected to treatments with artificial lighting systems. The net photosynthetic rate, stomatal conductance, substomatal CO2 concentration, transpiration rate, instantaneous water use efficiency, light compensation point and quantum yield were evaluated. In all the evaluated photosynthetic parameters, biotype R showed superior characteristics compared to susceptible biotypes, with the exception of the transpiration rate, where there were no differences. The differences between biotypes may not be associated to glyphosate resistance or susceptibility, but to the evolutionary characteristics of the biotypes. RESUMO: A resistência a herbicidas pode conferir menor capacidade competitiva, porém limitadas informações estão disponíveis sobre o desempenho fotossintético entre biótipos resistentes e suscetíveis ao glyphosate provenientes de área com similar histórico no manejo de plantas daninhas. Assim, o objetivo deste trabalho foi avaliar o desempenho fotossintético sob diferentes intensidades luminosas entre biótipos de buva resistente e suscetível ao glyphosate, oriundos de área de lavoura de soja Roundup Ready® com histórico similar de manejo de plantas daninhas. Os fatores testados foram biótipos resistentes e suscetíveis ao glyphosate e 12 níveis de densidade de fluxo de fótons fotossintéticos. As plantas foram cultivadas em copos plásticos e, no estádio de 10-12 folhas submetidas ao tratamento com sistema de luz artificial. Foram avaliados taxa fotossintética líquida, condutância estomática, concentração de CO2 subestomática, taxa transpiratória, eficiência instantânea do uso da água, ponto de compensação de luz e rendimento quântico. Em todos os parâmetros fotossintéticos avaliados, o biótipo R apresentou características superiores comparado ao biótipo suscetível, com exceção da taxa transpiratória, em que não houve diferenças. As diferenças entre biótipos podem não estar associadas à resistência ou suscetibilidade ao glyphosate, e sim às características evolutivas dos biótipos.
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- 2018
107. Response of Soybean Cultivars in Rotation with Irrigated Rice Crops Cultivated in Clearfield® System
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Francisco Amaral Villela, Leandro Vargas, André Andres, A.C.B. Oliveira, Dirceu Agostinetto, D.S. Fraga, LEANDRO VARGAS, CNPT., and ANDRE ANDRES, CPACT.
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Rotação de Cultura ,0106 biological sciences ,Irrigation ,Pesticide resistance ,Glycine max ,Physiology ,QH301-705.5 ,Planta daninha ,Oryza sativa ,Plant Science ,Biology ,01 natural sciences ,Biochemistry ,chemistry.chemical_compound ,Crop rotation ,Erva Daninha ,Cultivar ,Biology (General) ,Botany ,04 agricultural and veterinary sciences ,Imazapyr ,Imazapic ,Cultivance® ,chemistry ,Agronomy ,QK1-989 ,040103 agronomy & agriculture ,0401 agriculture, forestry, and fisheries ,Cultivance ,Phytotoxicity ,Soybeans ,Rice ,Weeds ,Agronomy and Crop Science ,010606 plant biology & botany ,Weedy rice - Abstract
Soybean crop rotation with irrigated rice is an alternative for the management of weedy rice (Oryza sativa) resistant to herbicides from the imidazolinone chemical group. This work had the purpose to evaluate the phytotoxicity of soybean crops containing the technologies Cultivance® (CV) and tolerance to sulphonylurea and Roundup Ready® (RR), deriving from increasing doses of the imazapyr and imazapic herbicide mixture, applied in the irrigated rice crop management. Thus, the experiment was performed on field, where treatments consisted in three soybean cultivars (BRS382CV, CD249STS and NA5909RR) and five doses of the imazapyr and imazapic herbicides mixture (0, 49, 98, 196 and 392 g a.i. ha-1). The evaluated variables were phytotoxicity, yield components and physiological quality of the seeds. Soybean cultivar BRS382CV is tolerant to herbicide carryover, applied in the management of weedy rice in irrigated rice crops, but the other cultivars are susceptible to it. Cultivar productivity, yield components and physiological quality of the seeds are affected by the carryover increase of the imazapyr and imazapic herbicide mixture. RESUMO: A rotação da cultura da soja ao arroz irrigado é alternativa para manejo de arroz-vermelho (Oryza sativa) resistente aos herbicidas do grupo químico das imidazolinonas. Objetivou-se avaliar a fitotoxicidade cultivares de soja contendo as tecnologias Cultivance® (CV) e tolerância às sulfonilureias (STS) e Roundup Ready® (RR), em decorrência do resíduo no solo de doses crescentes da mistura dos herbicidas imazapyr e imazapic, aplicados no manejo de plantas daninhas na cultura do arroz irrigado. O experimento foi realizado em campo, e os tratamentos consistiram de três cultivares de soja (BRS382CV, CD249STS e NA5909RR) e de cinco doses da mistura dos herbicidas imazapyr e imazapic (0, 49, 98, 196 e 392 g i.a. ha-1). As variáveis avaliadas foram fitotoxicidade, componentes da produtividade e qualidade fisiológica das sementes. O cultivar de soja BRS382CV é tolerante ao resíduo da mistura desses herbicidas, aplicado no manejo de arroz-vermelho na cultura do arroz irrigado, sendo os demais cultivares suscetíveis. A produtividade dos cultivares, os componentes de produtividade e a qualidade fisiológica das sementes de soja são afetados pelo aumento do resíduo da mistura dos herbicidas imazapyr e imazapic.
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- 2018
108. Properties of the enzyme acetolactate synthase in herbicide resistant canola
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Leandro Vargas, Franciele Mariani, Geraldo Chavarria, Fernando Machado dos Santos, Miria Rosa Durigon, MIRIA ROSA DURIGON, FRANCIELE MARIANI, FERNANDO MACHADO DOS SANTOS, LEANDRO VARGAS, CNPT, and GERALDO CHAVARRIA.
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0106 biological sciences ,0301 basic medicine ,food.ingredient ,Brassica Napus ,medicine.drug_class ,Materials Science (miscellaneous) ,Brassica napus L ,Canola ,Colza ,01 natural sciences ,imazapic ,03 medical and health sciences ,chemistry.chemical_compound ,Metsulfuron-methyl ,food ,enzyme functionality ,Imazapic ,medicine ,lcsh:Agriculture (General) ,Hybrid ,Triazine ,chemistry.chemical_classification ,Acetolactate synthase ,biology ,lcsh:S1-972 ,Sulfonylurea ,Horticulture ,030104 developmental biology ,Enzyme ,chemistry ,metsulfuron-methyl ,biology.protein ,General Agricultural and Biological Sciences ,010606 plant biology & botany - Abstract
Mutations in the gene that encodes the enzyme acetolactate synthase (ALS), conferring plant resistance to ALS inhibitor herbicides, can reduce or inhibit enzymatic function. The objective of this work was to determine the functionality and kinetic characteristics of the enzyme ALS and evaluate the action of the herbicides imazapic (imidazolinone) and metsulfuron-methyl (sulfonylurea) on the activity of the enzyme ALS in canola hybrid Hyola 571CL (imidazolinone resistant), compared to hybrids Hyola 555TT (triazine resistant) and Hyola 61 (conventional). The plants were grown in a greenhouse, and leaves were collected to perform ALS activity analysis. The concentration of pyruvate to provide initial velocity equal to half the maximum reaction rate (Km) and the maximum reaction rate (Vmax) was determined, as well as the enzyme’s activity in the presence of imazapic and metsulfuron-methyl inhibitors. There was no change in the Km and Vmax in the hybrid Hyola 571CL in relation to Hyola 61. The hybrid Hyola 555TT presented Vmax higher than the other hybrids. In the hybrid Hyola 571CL, the activity of ALS was reduced only by the application of metsulfuron-methyl, and the functionality of the enzyme did not change in relation to the other hybrids. The hybrid Hyola 571CL is resistant only to the imidazolinone group herbicide and this resistance does not cause adaptive cost in relation to the other hybrids.
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- 2018
109. Occupational exposure to chemicals, socioeconomic factors and Occupational Health: an integrated vision
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Rita de Cássia Oliveira da Costa Mattos, Leandro Vargas Barreto de Carvalho, Ariane Leites Larentis, and Isabele Campos Costa-Amaral
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Occupational health ,030504 nursing ,lcsh:Public aspects of medicine ,Compostos químicos ,lcsh:RA1-1270 ,General Medicine ,Occupational exposure ,Socioeconomic factors ,Saúde do trabalhador ,Chemical compounds ,03 medical and health sciences ,0302 clinical medicine ,Fatores socioeconômicos ,030212 general & internal medicine ,Exposição ocupacional ,0305 other medical science - Abstract
RESUMO A relação entre exposições ocupacionais, compostos químicos e doenças é conhecida há muito tempo e está no cerne do campo saúde-trabalho-ambiente. A pobreza presente na vida de numerosos trabalhadores brasileiros cria um cenário de vulnerabilidade social, gerando riscos à saúde. Este estudo tem por objetivo discutir a importância dos fatores socioeconômicos na avaliação da exposição ocupacional e a relação com o processo de saúde/doença dos trabalhadores, por meio de uma revisão exploratória da literatura. Diversos fatores estão ligados à forma como o trabalhador se relaciona com a exposição, como as condições de vida, moradia, acesso a serviços de saúde e educação, nível salarial e escolar. ABSTRACT The relationship between occupational exposures, chemical compounds and diseases has been known for a long time and is at the heart of the health-work-environment field. The condition of poverty in the lives of many Brazilian workers creates a scenario of social vulnerability, generating risks to health. This study aims to discuss the importance of socioeconomic factors in the evaluation of occupational exposure and the relationship with workers´ health/illness process, through an exploratory review of the literature. Several factors are related to how the worker relates to exposure, such as living conditions, housing, access to health and education services, salary levels and schooling.
- Published
- 2017
110. Agronomic factors involved in low-level wild poinsettia resistance to glyphosate
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Jessica Dias Gomes da Silva, Leandro Vargas, Bruno Moncks da Silva, Nixon da Rosa Westendorff, André da Rosa Ulguim, and Dirceu Agostinetto
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Resistance (ecology) ,biology ,Genetically modified crops ,Crop rotation ,Euphorbia heterophylla ,biology.organism_classification ,Horticulture ,chemistry.chemical_compound ,Geography ,Agronomy ,chemistry ,Glyphosate ,Herbicide resistance ,General Agricultural and Biological Sciences ,Poinsettia - Published
- 2017
111. COMPETITIVIDADE RELATIVA DE BIÓTIPOS DE CAPIM PÉ-DE-GALINHA COM A CULTURA DA SOJA
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Leandro Vargas, Lais Tessari Perboni, Jader Job Franco, Ana Claudia Langaro, and Dirceu Agostinetto
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0106 biological sciences ,Glycine max ,media_common.quotation_subject ,Eleusine indica ,01 natural sciences ,Genetically modified soybean ,Intraspecific competition ,Competition (biology) ,lcsh:Agriculture ,chemistry.chemical_compound ,Competição ,Soybean crop ,lcsh:QH301-705.5 ,media_common ,Glycine max. Eleusine indica. Competição. Resistência ,Resistência ,Competition ,biology ,Glycine max. Eleusine indica. Competition. Resistance ,fungi ,lcsh:S ,food and beverages ,04 agricultural and veterinary sciences ,Interspecific competition ,biology.organism_classification ,Agronomy ,chemistry ,lcsh:Biology (General) ,Glyphosate ,040103 agronomy & agriculture ,0401 agriculture, forestry, and fisheries ,Annual plant ,General Agricultural and Biological Sciences ,Resistance ,010606 plant biology & botany - Abstract
The goosegrass (Eleusine indica (L.) Gaertn) is an annual plant that has a low-level resistance to glyphosate (LLRG), resulting in control failure in genetically modified soybean crops for resistance to this herbicide. Alleles related to resistance may cause changes in the plant biotype, such as inferior competitive ability. Thus, the objective of this work was to evaluated the competitive ability of soybean crops and susceptible and resistant (LLRG) goosegrass biotypes. Replacement series experiments were conducted with soybean crops and goosegrass biotypes. The ratios of soybean to susceptible or resistant (LLRG) goosegrass plants were 100:0, 75:25, 50:50, 25:75 and 0:100, with a total population of 481 plants m-2. The leaf area, plant height and shoot dry weight were evaluated at 40 days after emergence of the soybean crops and weeds. The soybean crop had superior competitive ability to the susceptible and resistant (LLRG) goosegrass biotypes. The soybean crop showed similar competitive ability in both competitions, either with the susceptible or resistant (LLRG) goosegrass biotypes. The intraspecific competition was more harmful to the soybean crop, while the interspecific competition caused greater damage to the goosegrass biotypes competing with the soybean crop. RESUMO O capim pé-de-galinha (Eleusine indica (L.) Gaertn) é uma planta anual, que apresenta resistência de nível baixo (RNB) ao herbicida glifosato o que acarreta em falhas de controle em lavouras de soja geneticamente modificadas para resistência ao herbicida. Os alelos relacionados com a resistência podem acarretar em custos de adaptação ao biótipo, conferindo menor habilidade competitiva. Diante disso, o objetivo da pesquisa foi comparar a habilidade competitiva da cultura da soja com os biótipos de capim pé -de-galinha suscetível ou com RNB. Para isso, foram conduzidos experimentos em série de substituição entre a cultura da soja e os biótipos de capim pé-de-galinha. As proporções entre plantas de soja e capim pé-de-galinha suscetível ou com RNB foram de 100:0, 75:25, 50:50, 25:75 e 0:100, com população total de 481 plantas m -2. Avaliaram-se a área foliar (AF), estatura de planta (EST) e a massa da matéria seca da parte aérea (MMSPA), aos 40 DAE da cultura da soja e da planta daninha. A cultura da soja tem habilidade competitiva superior aos biótipos de capim pé-de-galinha suscetível ou com RNB. A habilidade competitiva da soja não foi diferencial frente à competição com os biótipos de capim pé-de-galinha suscetível ou com RNB. A competição intraespecífica para a cultura da soja e a competição interespecífica para os biótipos de capim pé-de-galinha, causam maiores danos aos competidores.
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- 2017
112. Morphophysiogenetic characterization of wild poinsettia biotypes with low resistance to glyphosate
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Leandro Vargas, Ana Claudia Langaro, Dirceu Agostinetto, Jessica Dias Gomes da Silva, André da Rosa Ulguim, Dirceu Agostinetto, UFPEL/FAEM/DF, André da Rosa Ulguim, Universidade Federal de Santa Maria - UFSM, LEANDRO VARGAS, CNPT, Jessica Dias Gomes da Silva, UFPEL/FAEM/DF, and Ana Claudia Langaro, UFPEL/FAEM/DF.
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0106 biological sciences ,AFLP ,competitive ability ,Agriculture (General) ,Euphorbia heterophylla ,01 natural sciences ,Genetic analysis ,resistance to herbicide ,S1-972 ,chemistry.chemical_compound ,ponto de compensação de luz ,Genotype ,Ight compensation point ,biology ,Euphorbia Heterophylla ,habilidade competitiva ,04 agricultural and veterinary sciences ,Amendoim bravo ,biology.organism_classification ,Resistência a herbicidas ,Herbicide resistance ,Horticulture ,Amplified fragment length polymorphism ,Compensation point ,chemistry ,resistência a herbicidas ,Glyphosate ,040103 agronomy & agriculture ,EPSPs inhibitor herbicide ,0401 agriculture, forestry, and fisheries ,Animal Science and Zoology ,Weeds ,light compensation point ,Low resistance ,Agronomy and Crop Science ,Poinsettia ,herbicida inibidor de EPSPs ,Erva daninha ,010606 plant biology & botany - Abstract
The objective of this work was to compare wild poinsettia (Euphorbia heterophylla) biotypes as to their morphological characteristics, as well as to determine their genetic similarity in the state of Rio Grande do Sul, Brazil, and to confront the light compensation point of susceptible biotypes and of biotypes with low-resistance level to glyphosate. Besides the morphology analysis, the study included the genetic characterization, by AFLP, of susceptible (GR50= 58.65 g ha-1 a.e.) biotypes and of biotypes with low resistance (GR50= 310.36 g ha-1 a.e.) to glyphosate. The competitive ability of the biotypes was inferred according to their light compensation point. The observed morphological characteristics do not allow to differentiate biotypes as to their geographical location, or their resistance level to glyphosate. The genetic analysis identified low genetic diversity among the 15 tested biotypes, with a large amount of subgroups. The biotypes with low resistance formed an isolated group. The susceptible biotypes showed the lowest values of light compensation point and, possibly, they have a greater competitive ability under low-luminosity conditions. The evaluated characteristics do not enable to differentiate genotypes with different levels of glyphosate resistance. Resumo: O objetivo deste trabalho foi comparar biótipos de leiteira (Euphorbia heterophylla) quanto a suas características morfológicas, assim como determinar sua similaridade genética no Rio Grande do Sul e confrontar o ponto de compensação de luz de biótipos suscetíveis e com baixa resistência ao glifosato. Além da análise morfológica, o estudo incluiu a caracterização genética, por meio de AFLP, dos biótipos suscetíveis (GR50= 58,65 g ha-1 e.a.) e dos biótipos com baixa resistência (GR50= 310,36 g ha-1 e.a.) ao glifosato. A habilidade competitiva dos biótipos foi inferida por meio de seus pontos de compensação de luz. As características morfológicas observadas não permitem diferenciar os biótipos quanto à localização geográfica ou ao grau de resistência ao glifosato. A análise genética identificou baixa diversidade genética entre os 15 biótipos de leiteira testados, com formação de elevado número de subgrupos. Os biótipos com baixa resistência formaram um grupo isolado. Os biótipos suscetíveis apresentaram os menores valores de ponto de compensação de luz e, possivelmente, têm maior habilidade competitiva em condições de baixa luminosidade. As características avaliadas não permitem diferenciar os genótipos com diferentes níveis de resistência ao glifosato.
- Published
- 2017
113. Avaliação da exposição a BTEX em postos de revenda de combustíveis no Rio de Janeiro, Brasil, e os riscos à saúde do trabalhador.
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Oliva Figueiredo, Victor, Barreto de Carvalho, Leandro Vargas, Marçullo Borges, Renato, Campos Costa-Amaral, Isabele, Corrêa dos Santos, Marcus Vinicius, Simões Rosa, Ana Cristina, Carneiro de Menezes, Marco Antônio, Oliveira da Costa Mattos, Rita de Cássia, Novaes Sarcinelli, Paula, Rabello Alves, Sergio, Leites Larentis, Ariane, and Simões Gonçalves, Eline
- Abstract
Copyright of Cadernos de Saude Publica is the property of Escola Nacional de Saude Publica Sergio Arouca and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
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- 2021
- Full Text
- View/download PDF
114. Oxidative Stress Levels Induced by Mercury Exposure in Amazon Juvenile Populations in Brazil
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Leandro Vargas Barreto de Carvalho, Isabele Campos Costa-Amaral, Beatriz Fátima Alves de Oliveira, Daniel Valente, Gabriela P. Silva, Sandra de Souza Hacon, Dennys de Souza Mourão, Ariane Leites Larentis, Rita de Cássia Oliveira da Costa Mattos, C. Vega, and Jucilene Aparecida Vieira
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Adult ,Male ,Rural Population ,Adolescent ,Health, Toxicology and Mutagenesis ,Population ,chemistry.chemical_element ,lcsh:Medicine ,Oxidative phosphorylation ,010501 environmental sciences ,Biology ,medicine.disease_cause ,mercury exposure ,01 natural sciences ,Article ,Dietary Exposure ,03 medical and health sciences ,chemistry.chemical_compound ,Animal science ,Rivers ,medicine ,Animals ,Humans ,Juvenile ,oxidative stress ,Child ,education ,030304 developmental biology ,0105 earth and related environmental sciences ,juvenile riverine communities ,0303 health sciences ,education.field_of_study ,lcsh:R ,Fishes ,Public Health, Environmental and Occupational Health ,biomarkers ,Mercury ,Glutathione ,MERCURY EXPOSURE ,Malondialdehyde ,Diet ,Mercury (element) ,Seafood ,chemistry ,Linear Models ,Female ,Brazil ,Water Pollutants, Chemical ,Oxidative stress - Abstract
Oxidative stress can be induced by mercury (Hg) exposure, including through fish consumption (diet), leading to health risks. The objective of this study was to evaluate the association between oxidative stress biomarkers and dietary Hg exposure levels in riverine children and adoluiaescents at Madeira River (RO/Brazil). Population from three riverine local communities presenting different fish consumption frequencies was sampled. Hg was determined in blood (ICP-MS) and glutathione (GSH), glutathione S-transferases (GST) and malondialdehyde (MDA) were determined in serum (spectrophotometry). Statistical analyses were performed using parametric and non-parametric tests. Multiple linear regression models and generalized additives models were also used to estimate the relationships between oxidative stress biomarkers and blood Hg. The juvenile riverine population from Cuniã, RESEX presented the highest levels of oxidative stress and Hg levels in blood (GST = 27.2 (4.93) U/L, MDA = 1.69 (0.27) µ, mol/L, Hg = 20.6 (18.0) µ, g/L). This population also presented the highest frequency of fish consumption. The positive relation between Hg and GST and MDA, adjusted for individual characteristics, suggests an oxidative effect. This study shows the importance of oxidative stress biomarkers in the evaluation of dietary Hg exposure since initial and reversible metabolic changes were observed, enriching health risk assessments.
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- 2019
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115. [Environmental surveillance of the steel industry by the people: the experiences of Piquiá de Baixo (MA) and Santa Cruz (RJ)]
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Leandro Vargas Barreto de, Carvalho, Flávio, Rocha, and Renan, Finamore
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Air Pollutants ,Steel ,Air Pollution ,Humans ,Particulate Matter ,Environmental Monitoring - Abstract
Environmental surveillance by the people fosters the protagonism of individuals in a situation of environmental vulnerability to generate and evaluate data regarding the pollution to which they are exposed. The scope of this work was to analyze such experiences in two areas impacted by the steel industry: Santa Cruz/RJ and Piquiá de Baixo/MA. At these sites, community environmental monitoring (CEM) activities were conducted to measure 2.5 micrometer particulate matter (PM2.5) levels in the atmosphere, between November/2016 and July/2017. Such activities were conducted using a low-cost and easy-to-operate air quality monitor. Monthly averages of PM2.5 levels in Piquiá and Santa Cruz were high, depending on the period assessed, since they surpassed the annual average recommended by the World Health Organization (WHO) of 10 µg/m3, and, on several occasions, the recommended daily average of 25 µg/m3. The main idea of this monitoring proposal was to establish a process capable of presenting a counterpoint to official information on local atmospheric pollution scenarios, with the involvement of affected communities. The pollution data produced enable these communities to participate in public debates and decision-making processes in a more informed way.A vigilância popular ambiental (VPA) promove o protagonismo dos sujeitos em situação de vulnerabilidade ambiental na produção e avaliação de dados sobre a poluição a que estão submetidos. O objetivo deste trabalho foi analisar as experiências de VPA desenvolvidas em duas localidades impactadas por siderúrgicas: Santa Cruz/RJ e Piquiá de Baixo/MA. Nesses locais foram realizadas atividades de monitoramento ambiental comunitário (MAC) dos níveis de material particulado de 2,5 micrômetros (MP2,5) na atmosfera, entre novembro de 2016 e julho de 2017, utilizando equipamento monitor de qualidade do ar de baixo custo e fácil operação. As médias mensais dos níveis de MP2,5 em Piquiá e Santa Cruz foram elevadas, a depender da época avaliada, pois ultrapassaram a média anual recomendada pela Organização Mundial de Saúde (OMS), de 10 µg/m3, e por várias vezes a média diária recomendada, de 25 µg/m3. A ideia principal desta proposta de monitoramento consistiu em estabelecer, com o engajamento das comunidades atingidas, um processo capaz de apresentar um contraponto às informações oficiais sobre cenários locais de poluição atmosférica. Os dados de poluição produzidos possibilitam que essas comunidades tenham uma atuação mais qualificada nos espaços públicos de debate e tomada de decisão.
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- 2019
116. Environmental Assessment and Evaluation of Oxidative Stress and Genotoxicity Biomarkers Related to Chronic Occupational Exposure to Benzene
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Maria José Nunes de Paiva, Vanessa G Milagres, Marcus Vinicius Corrêa dos Santos, Isabele Campos Costa-Amaral, Maria de Fátima Trancoso, Leiliane Coelho André, Marco Antônio Carneiro Menezes, Sérgio Rabello Alves, Herbert Ary Sisenando, Daniel Valente, Juliana Mendonça de Souza, Eline Simões Gonçalves, Rita de Cássia Oliveira da Costa Mattos, Jamila A Perini, Victor Figueiredo, Michele Polyana Rocha Mendes, Paula de Novaes Sarcinelli, Andrew Collins, Monica Stuck de Oliveira, Antônio Sérgio Almeida Fonseca, Renato Marçullo Borges, Leandro Vargas Barreto de Carvalho, Liliane Reis Teixeira, Angélica Cardoso Pereira, Maria Juliana Moura-Correa, Ariane Leites Larentis, and Vinicio Soares de Castro
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Male ,Health, Toxicology and Mutagenesis ,Physiology ,genotoxicity and formamidopyrimidine DNA-glycosylase ,lcsh:Medicine ,010501 environmental sciences ,medicine.disease_cause ,01 natural sciences ,chemistry.chemical_compound ,benzene ,Malondialdehyde ,oxidative stress ,Benzene ,Glutathione Transferase ,0303 health sciences ,biology ,Middle Aged ,occupational and environmental health ,Female ,Comet Assay ,Brazil ,Environmental Monitoring ,Adult ,Adolescent ,Air Pollutants, Occupational ,chronic exposure ,Article ,Superoxide dismutase ,Young Adult ,03 medical and health sciences ,Occupational Exposure ,medicine ,Humans ,Carcinogen ,030304 developmental biology ,0105 earth and related environmental sciences ,Chromosome Aberrations ,business.industry ,lcsh:R ,Public Health, Environmental and Occupational Health ,Glutathione ,Acetylcysteine ,Comet assay ,chemistry ,Carcinogens ,biology.protein ,business ,Biomarkers ,Genotoxicity ,Oxidative stress ,DNA Damage ,Toluene - Abstract
Environmental and occupational exposure to benzene from fuels is a major cause for concern for national and international authorities, as benzene is a known carcinogen in humans and there is no safe limit for exposure to carcinogens. The objective of this study was to evaluate the genotoxic effects of chronic occupational exposure to benzene among two groups of workers: filling station workers (Group I) and security guards working at vehicles entrances (Group II), both on the same busy highway in Rio de Janeiro, Brazil. Sociodemographic data on the workers were evaluated, the concentration of benzene/toluene (B/T) in atmospheric air and individual trans,trans-muconic acid (ttMA) and S-phenylmercapturic acid (S-PMA) were measured, oxidative stress was analyzed by catalase (CAT), glutathione S-transferase (GST), superoxide dismutase (SOD), thiol groups (THIOL) and malondialdehyde (MDA), genotoxicity was measured by metaphases with chromosomal abnormalities (MCA) and nuclear abnormalities, comet assay using the enzyme formamidopyrimidine DNA glycosylase (C-FPG), and methylation of repetitive element LINE-1, CDKN2B and KLF6 genes. Eighty-six workers participated: 51 from Group I and 35 from Group II. The B/T ratio was similar for both groups, but Group I had greater oscillation of benzene concentrations because of their work activities. No differences in ttMA and S-PMA, and no clinical changes were found between both groups, but linearity was observed between leukocyte count and ttMA, and 15% of workers had leukocyte counts less than 4.5 ×, 109 cells L&minus, 1, demanding close worker&rsquo, s attention. No differences were observed between the two groups for THIOL, MDA, MCA, or nuclear abnormalities. A multiple linear relationship was obtained for the biomarkers MCA and C-FPG. A significant correlation was found between length of time in current job and the biomarkers C-FPG, MCA, GST, and MDA. Although both populations had chronic exposure to benzene, the filling station workers were exposed to higher concentrations of benzene during their work activities, indicating an increased risk of DNA damage.
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- 2019
117. Resistência de nível baixo de biótipos de leiteira ao glyphosate e alternativas químicas de controle
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Leandro Vargas, Jessica Dias Gomes da Silva, André da Rosa Ulguim, Bruno Moncks da Silva, Dirceu Agostinetto, and Renan Ricardo Zandoná
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biology ,Resistance (ecology) ,Agricultural Sciences ,QH301-705.5 ,euphorbia heterophylla ,Agriculture ,biology.organism_classification ,Euphorbia heterophylla ,resistance factor ,chemistry.chemical_compound ,Horticulture ,chemistry ,Glyphosate ,dose response ,Biology (General) ,General Agricultural and Biological Sciences ,Chemical control ,Poinsettia ,weed - Abstract
In the State of Rio Grande do Sul (RS), Southern Brazil, glyphosate has not been capable of controlling wild poinsettia (Euphorbia heterophylla L.) in soybean fields, thus, suggesting resistance to this herbicide. Therefore, this study aimed at evaluating sensitivity of wild poinsettia biotypes to glyphosate, identifying the occurrence of resistance of wild poinsettia to the herbicide in RS state and determining the resistance factor of wild poinsettia biotypes under suspicion, besides assessing other herbicides as alternative controls. Two greenhouse experiments, which lasted two years, were conducted by a completely randomized design with four replications. Six biotypes (Factor A) and eight doses of glyphosate (Factor B) were used for getting the dose-response curve. Regarding the alternative control, post-emergence herbicides for soybean and corn crops were tested. Control and dry mass of the shoot were analyzed as variables. Resistance factors of resistant biotypes 20.2 and 21.1 were 4.83 and 5.29, respectively, by comparison with the susceptible biotype (11.4). In RS state, there has currently been high selection pressure due to the intensive use of glyphosate against wild poinsettia plants, as the result of the occurrence of biotypes 20.2 and 21.1 which have low levels of resistance to glyphosate and very little control by ALS-inhibiting herbicides. Therefore, an alternative to mitigate the problem is the use of herbicides with different mechanisms of action. As falhas de controle de leiteira (Euphorbia heterophylla L.) após aplicação de glyphosate em lavouras de soja do Rio Grande do Sul (RS) são frequentes, sugerindo a resistência ao herbicida. Diante disso, os objetivos foram avaliar a sensibilidade de biótipos de leiteira ao herbicida glyphosate, identificar a ocorrência da resistência, determinar o fator de resistência de biótipos de leiteira com suspeita de resistência e avaliar herbicidas alternativos para o seu controle. Foram conduzidos dois experimentos em casa de vegetação, em delineamento inteiramente casualizado com quatro repetições ambos realizados em dois anos. No experimento de curva dose-resposta foram utilizados cinco biótipos (fator A) e oito doses do herbicida glyphosate (fator B). Para o controle alternativo, foram testados herbicidas em pós emergência das culturas de soja e milho. As variáveis analisadas foram controle e massa seca da parte aérea. O fator de resistência dos biótipos resistentes (20.2 e 21.1) foram 4,83 e 5,29 comparativamente ao biótipo suscetível (11.4) respectivamente. Existe elevada pressão de seleção pelo glyphosate em plantas de leiteira no RS, observando-se a ocorrência de biótipos 20.2 e 21.1 com resistência de nível baixo ao herbicida e com controle reduzido pelos herbicidas inibidores de ALS. Portanto, uma alternativa para atenuar o problema é o uso de herbicidas com diferentes mecanismos de ação.
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- 2019
118. Does the Glyphosate Treatment Interfere Negatively on RNA Integrity in Glyphosate-Resistant and -Sensitive Conyza bonariensis?
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Cristiano Piasecki, Daiane de Pinho Benemann, Dirceu Agostinetto, Ivan Ricardo Carvalho, Leandro Vargas, and C.N. Stewart
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QH301-705.5 ,Physiology ,buva ,Plant Science ,RNA integrity number ,Biology ,hairy fleabane ,Biochemistry ,análises moleculares ,law.invention ,chemistry.chemical_compound ,law ,molecular analysis ,Biology (General) ,RNA integrity number (RIN) ,Polymerase chain reaction ,chemistry.chemical_classification ,Gel electrophoresis ,Reactive oxygen species ,Botany ,RNA ,Weed science ,número de integridade do RNA (RIN) ,Molecular analysis ,chemistry ,QK1-989 ,Glyphosate ,Agronomy and Crop Science - Abstract
The hairy fleabane ( Conyza bonariensis (L.) Cronq.) is among the most problematic glyphosate-resistant weeds to manage around the world. In weed science, molecular approaches such as RNA sequencing (RNA-Seq) and quantitative reverse-transcription polymerase chain reaction (RT-qPCR) have been employed to study molecular responses to glyphosate treatment in Conyza species. Glyphosate treatment leads to reactive oxygen species (ROS) production in plants which could damage the RNA. Degraded RNA is an issue and can compromise further molecular analysis. Thus, the objective of this study was to evaluate whether glyphosate treatment interferes negatively on RNA integrity of glyphosate-resistant and -sensitive hairy fleabane biotypes. Two experiments were performed using glyphosate doses from 0 to 11,840 g a.e. ha-1 and evaluated in a time-course until 288 hours after treatment. The total of 86 RNA samples were evaluated. The RNA integrity was evaluated in a Bioanalyzer 2100 equipment according to RNA integrity number (RIN) scores and electrophoresis gel. The RIN scores ranged from 5.1 to 9.0. Glyphosate doses do not reduce the RIN scores in both glyphosate-resistant and -sensitive biotypes of hairy fleabane. Visual and automatic analysis of electrophoresis gel show suitable results for all RNA samples, with well-defined bands at 28S and 18S positions and no degradation. The results of the analysis indicate that glyphosate treatment does not affect the RNA integrity of glyphosate-resistant and -sensitive biotypes of hairy fleabane until 288 and 192 hours after glyphosate treatment, respectively. The RNA integrity analysis provides useful results to evaluate the RNA condition for further analysis. However, the costs were around US$ 14.25 per sample, considering only reagents. These results are useful for planning future time-course experiments in Conyza spp. after glyphosate treatment. RESUMO: A buva (Conyza bonariensis (L.) Cronq.) está entre as plantas daninhas resistentes ao glifosato mais difíceis de serem manejadas em todo o mundo. Na ciência das plantas daninhas, abordagens moleculares, como o sequenciamento de RNA (RNA-Seq) e a reação da transcriptase reversa da polimerase em tempo real (RT-qPCR), têm sido empregadas para estudar as respostas moleculares ao tratamento com glifosato em espécies de Conyza. No entanto, o tratamento com glifosato leva à produção de espécies reativas de oxigênio (ROS) em plantas, que podem danificar o RNA. A degradação do RNA é um problema e pode comprometer futuras análises moleculares. Assim, o objetivo deste estudo foi avaliar se o tratamento com glifosato interfere negativamente na integridade do RNA de biótipos de buva resistente e sensível ao glifosato. Dois experimentos foram realizados utilizando doses de glifosato de 0 a 11.840 g e.a. ha-1 e avaliados em um tempo de até 288 horas após o tratamento. O total de 86 amostras de RNA foram avaliadas. A integridade do RNA foi avaliada em um equipamento Bioanalyzer 2100 de acordo com escores de número de integridade de RNA (RIN) e em gel de eletroforese. Os escores do RIN variaram de 5,1 a 9,0. Doses de glifosato não reduziram os escores do RIN em biótipos de buva resistentes e sensíveis ao glifosato. A análise visual e automática do gel de eletroforese mostrou resultados adequados para todas as amostras de RNA, com bandas bem definidas nas posições 28S e 18S e sem degradação. Os resultados da análise indicam que o tratamento com glifosato não afeta negativamente a integridade do RNA dos biótipos resistentes e sensíveis ao glifosato da buva até 288 e 192 horas após o tratamento com glifosato, respectivamente. A análise da integridade do RNA fornece resultados úteis. Entretanto, os custos são altos e ficaram em torno de US $ 14,25 por amostra, considerando apenas os reagentes. Esses resultados são úteis para o planejamento de experimentos futuros em Conyza spp. após o tratamento com glifosato.
- Published
- 2019
119. Fitness Cost and Competitive Ability to Different Ploidy Levels in Ryegrass Genotypes
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Leandro Vargas, Jonas Rodrigo Henckes, Maicon Fernando Schmitz, Cristiano Piasecki, Joanei Cechin, and Dirceu Agostinetto
- Subjects
QH301-705.5 ,Physiology ,media_common.quotation_subject ,competição ,Population ,Plant Science ,diploid ,Biochemistry ,Competition (biology) ,Dry weight ,Lolium multiflorum ,Genotype ,tetraploide ,Biology (General) ,education ,media_common ,education.field_of_study ,biology ,Phenology ,fungi ,Botany ,food and beverages ,manejo integrado de plantas daninhas ,biology.organism_classification ,tetraploid ,Agronomy ,integrated weed management ,QK1-989 ,Ploidy ,diploide ,competition ,Agronomy and Crop Science ,Fitness cost - Abstract
The intergenotypic competition of tetraploid ryegrass with natural diploid population may be a tool to reduce the frequency of resistant individuals in an area. This study aimed to identify and compare the phenological development, fitness cost, and competitive ability between diploid and tetraploid ryegrass genotypes. Genotypes were grown in pots, and the morphological variables of genotype growth were assessed every 15 days up to 120 days after emergence to evaluate the fitness cost. Phenological development and seed yield components were measured in a single time together with the fitness cost. Competitive ability was determined in a replacement-series experiment with proportions of tetraploid and diploid ryegrass, in which the number of tillers, plant height, leaf area, and shoot dry weight were assessed at 50 days after emergence. The results of fitness cost showed that the number of tillers, leaf area, root dry weight, and the number of seeds were higher for tetraploid ryegrass, which presented a higher competitive ability than the diploid genotype regardless of the tested proportions. Tetraploid ryegrass may be useful for reducing the frequency of herbicide-resistant diploid ryegrass because of its higher competitive potential. RESUMO: A competição intergenotípica de azevém tetraploide com a população natural diploide pode ser uma ferramenta para reduzir a frequência de indivíduos resistentes em uma área. O objetivo deste estudo foi identificar e comparar o desenvolvimento fenológico, custo adaptativo e habilidade competitiva entre genótipos de azevém diploide e tetraploide. Para avaliar o custo adaptativo, os genótipos foram cultivados em vasos, e as variáveis morfológicas de crescimento dos genótipos, avaliadas a cada 15 dias até os 120 dias após a emergência. O desenvolvimento fenológico e os componentes de produtividade das sementes foram mensurados em época única, em conjunto com o custo adaptativo. A habilidade competitiva foi determinada em experimento de série de substituição com proporções de azevém tetraploide e diploide, em que o número de afilhos, estatura, área foliar e massa seca da parte aérea foram avaliados aos 50 dias após a emergência. Os resultados de custo adaptativo demonstraram que o número de afilhos, a área foliar, a massa seca de raiz e o número de sementes foram superiores para o azevém tetraploide e que este apresenta maior habilidade competitiva comparativamente ao diploide, independente das proporções testadas. O azevém tetraploide, por apresentar maior potencial competitivo, pode ser útil para redução da frequência de azevém diploide resistente a herbicidas.
- Published
- 2019
120. Herança da Resistência de Lolium multiflorum ao Iodosulfuron-Methyl Sodium
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Franciele Mariani, Diecson Ruy Orsolin da Silva, Leandro Vargas, D.S. Fraga, D. Agostinetto, B.M. Silva, IFRGS, LEANDRO VARGAS, CNPT, UFPEL, UFSM, and UFPEL.
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biology ,QH301-705.5 ,Physiology ,Herbicida ,Lolium spp ,genetics ,Botany ,Herbicide ,Plant Science ,Lolium multiflorum ,genética ,biology.organism_classification ,Genética ,Biochemistry ,Horticulture ,QK1-989 ,herbicida ,Biology (General) ,Agronomy and Crop Science - Abstract
RESUMO - Populacoes de azevem resistente aos inibidores da enzima ALS tem aumentado rapidamente nos campos cultivados. Para o manejo da resistencia, sao necessarios estudos de heranca da resistencia, os quais permitem entender a evolucao da resistencia, a estrutura genetica da populacao e a dinâmica de adaptacao dos biotipos resistentes. Este trabalho teve como objetivo identificar o tipo de heranca, o numero de genes envolvidos e o grau de resistencia dos biotipos de azevem, homozigotos e heterozigotos, resistentes ao iodosulfuron. A partir da selecao dos biotipos homozigoto resistente (R) e homozigoto suscetivel (S), foram realizados cruzamentos (R x S) para obtencao de plantas F1, e estas, cruzadas para obtencao da F2, e realizaram-se retrocruzamentos entre plantas F1 e os respectivos genitores masculinos e femininos resistentes (RCr) e sensiveis (RCs). As sementes F1, F2, RCr, RCs e dos genitores foram semeadas em bandejas e avaliadas, com aplicacao do iodosulfuron, quanto a sua suscetibilidade ou resistencia. Plantas F1 e dos genitores foram tratadas com doses crescentes do herbicida. A avaliacao de controle dessas plantas pelo iodosulfuron foi feito por meio de notas (0 a 100), referentes aos sintomas de intoxicacao e pela massa da materia seca da parte aerea acumulada. Os genitores masculino ou feminino transmitiram a caracteristica para a prole, sendo esta 100% resistente, indicando gene de resistencia dominante. A geracao F2 apresentou segregacao 3:1 resistente/suscetivel, confirmando a caracteristica de dominância. O teste de dominância das plantas F1 evidenciou que as plantas homozigotas resistentes e as heterozigotas apresentam grau de resistencia semelhante. Conclui-se que a resistencia do azevem ao iodosulfuron e codificada por gene dominante nuclear com dominância completa. Palavras-chave: Lolium spp., genetica, herbicida.
- Published
- 2015
121. Vigilância popular ambiental e siderurgia: as experiências de Piquiá de Baixo (MA) e Santa Cruz (RJ), Brasil.
- Author
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Barreto de Carvalho, Leandro Vargas, Rocha, Flávio, and Finamore, Renan
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AIR quality monitoring ,PARTICULATE matter ,ENVIRONMENTAL monitoring ,STEEL industry ,POLLUTION - Abstract
Copyright of Revista Ciência & Saúde Coletiva is the property of Associacao Brasileira de Pos-Graduacao em Saude Coletiva and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
- Published
- 2021
- Full Text
- View/download PDF
122. COMPETITION BETWEEN WHEAT AND RYEGRASS UNDER DIFFERENT LEVELS OF NITROGEN FERTILIZATION
- Author
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Camila Peligrinotti Tarouco, Leandro Vargas, Dirceu Agostinetto, José Orlando Gomes, Ana Claudia Langaro, DIRCEU AGOSTINETTO, UFPel, UFPel, and LEANDRO VARGAS, CNPT.
- Subjects
0106 biological sciences ,QH301-705.5 ,Physiology ,media_common.quotation_subject ,Triticum aestivum ,chemistry.chemical_element ,Trigo ,Context (language use) ,Plant Science ,série substitutiva ,Biology ,01 natural sciences ,Biochemistry ,nitrogen ,Competition (biology) ,Nutrient ,Lolium multiflorum ,Dry matter ,Biology (General) ,Triticum Aestivum ,Azevém ,media_common ,fungi ,Botany ,food and beverages ,04 agricultural and veterinary sciences ,Interspecific competition ,biology.organism_classification ,Nitrogen ,nitrogênio ,chemistry ,Agronomy ,QK1-989 ,Wheat ,040103 agronomy & agriculture ,replacement series ,0401 agriculture, forestry, and fisheries ,Weed ,Agronomy and Crop Science ,010606 plant biology & botany - Abstract
The main limiting factors for the productive potential of wheat crops are related to the competition with weeds for resources such as water, light and nutrients. Nitrogen (N) is an important nutrient used to maintain crop productivity, as well as promoting the competitive ability of crops and therefore suppress the weed growth. In this context, the goal of this study was to evaluate the effects of wheat plants in competition with ryegrass under different levels of nitrogen fertilization. Treatments were arranged in a factorial design, where factor A consisted in nitrogen rates (0, 60, 120, 180 and 240 kg ha-1) and factor B consisted in ryegrass and wheat plants ratios, which were: 100/0 (pure stand of 64 wheat plants), 50/50 (32 wheat plants and 32 ryegrass plants) and 0/100 (pure stand of 64 ryegrass plants). Competition between the culture and ryegrass by N resulted in mutual damages, but the culture was more competitive than weeds, regardless of the N dose. The use of doses up to 120 kg N ha-1 increased the evaluated variables for wheat and ryegrass. Interspecific competition and nitrogen in higher than 120 kg N ha-1 doses reduced the morphological variables mass of the aerial part dry matter and leaf area of wheat and ryegrass. RESUMO Os principais fatores limitantes do potencial produtivo da cultura do trigo estão relacionados à competição das plantas daninhas por recursos como água, luz e nutrientes. O nitrogênio (N) é importante nutriente utilizado para manter a produtividade das culturas, além de favorecer a habilidade competitiva da cultura e, com isso, suprimir o crescimento das plantas daninhas. Nesse contexto, o objetivo deste trabalho foi avaliar os efeitos da competição de plantas de trigo e azevém sob diferentes níveis de adubação nitrogenada. Os tratamentos foram arranjados em esquema fatorial, em que o fator A constituiu-se de doses de nitrogênio (0, 60, 120, 180 e 240 kg ha-1) e o fator B, de proporções de plantas de azevém e trigo, as quais foram: 100/0 (estande puro de 64 plantas de trigo), 50/50 (32 plantas de trigo e 32 plantas de azevém) e 0/100 (estande puro de 64 plantas de azevém). A competição entre a cultura e o azevém pelo N acarretou prejuízo mútuo, porém a cultura mostrou maior competitividade do que a planta daninha, independentemente da dose de N. A utilização de doses até 120 kg N ha-1 aumentaram as variáveis avaliadas para o trigo e para o azevém. A competição interespecífica e o nitrogênio nas doses superiores a 120 kg N ha-1 reduziram as variáveis morfológicas massa da matéria seca da parte aérea e área foliar do trigo e do azevém.
- Published
- 2017
123. Alternativas de controle químico para capim-amargoso (Digitaria insularis) na cultura do milho
- Author
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Wilton Tavares Silva, Leandro Vargas, Alexandre Ferreira da Silva, Décio Karam, Wilton Tavares da Silva, Estagiário, DECIO KARAM, CNPMS, LEANDRO VARGAS, CNPT, and ALEXANDRE FERREIRA DA SILVA, CNPMS.
- Subjects
Developmental stage ,biology ,Planta daninha ,Randomized block design ,General Medicine ,biology.organism_classification ,Mesotrione ,chemistry.chemical_compound ,Horticulture ,chemistry ,Glyphosate ,Herbicida ,Atrazine ,Resistência ,Chemical control ,Weed ,Digitaria insularis ,Erva daninha - Abstract
RESUMO – O presente estudo teve por objetivo avaliar a eficacia de herbicidas pos-emergentes registrados para a cultura do milho, assim como futuras alternativas de controle quimico, no manejo de biotipos de capim-amargoso resistente ao glyphosate. Tres experimentos, em condicao de casa de vegetacao, foram realizados no delineamento de blocos ao caso, com tres repeticoes. Herbicidas de reconhecida eficiencia agronomica no controle de gramineas na cultura do milho (tembotrione, mesotrione e nicosulfuron) e futura alternativas de controle quimico (haloxyfop-p-methyl e ammonium-glufosinate) foram aplicados em diferentes periodos de desenvolvimento sobre o capim-amargoso. Foram avaliados os sintomas de intoxicacao e a porcentagem de reducao do acumulo da massa de materia seca (MMS) da infestante apos a ultima avaliacao de controle. Os herbicidas nicosulfuron, haloxyfop-p-methyl e ammonium-glufosinate ocasionaram a morte da planta independentemente do momento de aplicacao. Tembotrione e mesotrione, apesar de reduzirem a porcentagem de acumulo da MMS, nao ocasionaram morte das plantas. Conclui-se que o nicosulfuron se caracteriza como importante ferramenta no controle de capim-amargoso. As moleculas haloxyfop-p-methyl e ammonium-glufosinate apresentam potencial para serem utilizadas como alternativas de controle quimico da infestante. Os herbicidas tembotrione e mesotrione, apesar de reconhecida acao graminicida, nao sao indicados para o controle do capim-amargoso. Palavras-chave: Zea mays , herbicidas, resistencia, planta daninha. ALTERNATIVES OF CHEMICAL CONTROL FOR SOURGRASS ( Digitaria insularis ) ON MAIZE CROP ABSTRACT – This study aimed to evaluate the efficacy of registered herbicides for weed control in maize crop and to test future alternatives of chemical control for management of sourgrass biotypes resistant to glyphosate. Three experiments, in the greenhouse, were carried out in a randomized block design with three replicates. Herbicides of recognized agronomic efficiency in grass control on maize (tembotrione, mesotrione and nicossulfuron) and future alternatives of chemical control (haloxyfop-p-methyl e ammonium-glufosinate), as well as, standard herbicide treatment used on maize off-season glyphosate resistant (glyphosate + atrazine), were sprayed on sourgrass plants at different growth periods. The parameters evaluated were intoxication symptoms and the decrease in dry mass accumulation. The herbicides nicossulfuron, haloxyfop-p-methyl and ammonium-glufosinate caused the death of plants, regardless of their developmental stage. In spite of causing a decrease in weed dry mass accumulation, tembotrione and mesotrione did not cause plant death. It is concluded that nicossulfuron is characterized as an important tool in control of sourgrass. The molecules haloxyfop-p-methyl and ammonium-glufosinate have potential to be used as alternatives to control this infestant. The herbicides tembotrione and mesotrione despite recognized grass control were notindicated to control of sourgrass. Keywords: Zea mays , herbicide, resistance, weed.
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- 2017
124. Perda de rendimento da soja e nível de dano econômico pela interferência de buva resistente ao glifosato
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Diecson Ruy Orsolin da Silva, Leandro Vargas, Dirceu Agostinetto, DIRCEU AGOSTINETTO, UFPEL, DIECSON RUY ORSOLIN DA SILVA, UFSM, and LEANDRO VARGAS, CNPT.
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hipérbole retangular ,Agriculture (General) ,Soja ,competição ,densidade de planta daninha ,Biology ,Population density ,rectangular hyperbole ,S1-972 ,weed control cost ,chemistry.chemical_compound ,Yield (wine) ,Buva ,Cultivar ,Economic threshold ,Crop yield ,General Medicine ,Weed control ,custo de controle de planta daninha ,Agronomy ,chemistry ,Glyphosate ,weed density ,Conyza bonariensis ,Weed ,competition ,Erva daninha ,Soybean - Abstract
The interference of glyphosate resistant hairy fleabane (Conyza bonariensis) has caused yield losses in soybean crop. Knowledge of the economic threshold is an important aspect for the economic management of resistant weeds. Because of it, the interference of the glyphosate resistant hairy fleabane density on the soybean yield loss was evaluated, as well as to estimate the economic threshold. Two experiments were conducted to verify the effect of different weed densities on the yield of two soybean cultivars (BRS Estância and BMX Turbo). Weed density ranged from 0 to 124 plants m-2. The yield of the BRS Estância decreased by 1.4% to the increase of one single plant, while for the BMX Turbo the loss was 25.9%. Soybean yield and economic threshold were lower for the BMX Turbo cultivar compared to the cultivar BRS Estância, which can be attributed to the genotype, competitive ability, weed development stage and/or environment. Increases in crop yield expectation, soybean price and herbicide efficiency reduce the economic threshold, indicating that the adoption of control measures should be taken when the weed density is low. Due to the high cost of hairy fleabane control, it is only feasible at high densities. RESUMO: A interferência de plantas de buva (Conyza bonariensis) resistente ao herbicida glyphosate tem causado perdas de produtividade na cultura da soja. O conhecimento do nível de dano econômico é um importante fator para o manejo econômico de plantas daninhas resistentes na cultura da soja. Para isso, foi avaliada a interferência da densidade de buva resistente ao glyphosate sobre a perda de rendimento da soja, bem como estimado o nível de dano econômico. Dois experimentos foram conduzidos para verificar o efeito de diferentes densidades da planta daninha sobre a produtividade de dois cultivares de soja (BRS Estância e BMX Turbo). As densidades de buva variaram de 0 a 124 plantas m-2. A produtividade do cultivar BRS Estância reduziu 1,4% ao aumento de uma planta, enquanto para o cultivar BMX Turbo a perda foi de 25,9%. A produtividade da soja e o nível de dano econômico foram menores para o cultivar BMX Turbo, em comparação com o cultivar BRS Estância, o que pode ser atribuído ao genótipo, à habilidade competitiva, ao estádio de desenvolvimento da buva e/ou a ambiente. Aumentos na expectativa de produtividade da cultura, no preço da soja e na eficiência dos herbicidas reduzem o nível de dano econômico, indicando que a adoção de medidas de controle deve ser tomada quando a população de buva é baixa. Em função do elevado custo de controle da buva, este somente é viável em altas densidades.
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- 2017
125. Differential susceptibility of biotypes of conyza sumatrensis to Chlorimuron-ethyl herbicide
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Leandro Vargas, T. Dal Magro, Franciele Mariani, Pedro Jacob Christoffoleti, Dirceu Agostinetto, Filipe Martins Santos, IFRS Sertão, LEANDRO VARGAS, CNPT, USP - ESALQ, UFPel, and UCS.
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Physiology ,QH301-705.5 ,Planta daninha ,Plant Science ,horseweed ,Biochemistry ,Conyza sumatrensis ,chemical control ,Shoot dry weight ,Buva ,Botany ,Resistência de nível baixo ,Biology (General) ,Horseweed ,Completely randomized design ,low level resistance ,biology ,food and beverages ,Chlorimuron ethyl ,biology.organism_classification ,Weed control ,Weed ,Controle Químico ,Horticulture ,QK1-989 ,Low level resistance ,ALS ,Agronomy and Crop Science - Abstract
Horseweed (Conyza spp.) is an annual weed, infesting soybean crops in southern Brazil, with chlorimuron-ethyl being one of the most commonly used herbicides for its control. However, in recent soybean harvests, an unsatisfactory control of this weed using this herbicide was observed, generating suspicion regarding the selection of resistant biotypes. The objective of this study was to evaluate the susceptibility of horseweed biotypes to the herbicide chlorimuron-ethyl. Two experiments were conducted in a greenhouse; in the first one, the biotypes were selected selected, and the second experiment was arranged in a 5 x 5 factorial in a completely randomized design with four replications. The treatments used in the preparation of the dose response curves were doses of the herbicide chlorimuron-ethyl (0.0, 1.56, 3.13, 6.25, 12.5, and 25 g ha-1), applied on the five horseweed biotypes at the 3-4 leaf growth stage. The variables evaluated were visual control percentage and shoot dry weight, compared to the control without herbicide application, and plant acetolactate accumulation. It was concluded that there is a differential susceptibility among the biotypes at doses of less than 20 g ha-1 (dose response curves), which indicates low-level resistance. The practical consequences are the indications of chlorimuron-ethyl application at the maximum doses recomended and that the practice of rotating mechanisms of action must be used in the chemical weed management of these areas.
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- 2014
126. Distribuição Geográfica de Azevém Resistente ao Herbicida Clethodim no Rio Grande do Sul
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M. A. Bianchi, T. Schneider, Leandro Vargas, and Dirceu Agostinetto
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0106 biological sciences ,QH301-705.5 ,Physiology ,Plant Science ,01 natural sciences ,Biochemistry ,resistance ,chemistry.chemical_compound ,chemical control ,Lolium multiflorum ,Acetyl-coenzyme A carboxylase ,Continuous use ,Biology (General) ,controle químico ,acetyl coenzima A carboxilase ,biology ,fungi ,Botany ,food and beverages ,04 agricultural and veterinary sciences ,biology.organism_classification ,resistência ,Geographic distribution ,chemistry ,Agronomy ,QK1-989 ,Glyphosate ,040103 agronomy & agriculture ,0401 agriculture, forestry, and fisheries ,acetyl coenzyme A carboxylase ,Chemical control ,Weed ,Agronomy and Crop Science ,010606 plant biology & botany - Abstract
Ryegrass is a weed of annual cycle that is present in winter crops, in orchards and vineyards of the South region of Brazil. The species is normally controlled by the glyphosate herbicide, but the continuous use of this product caused the selection of resistant biotypes. The use of ACCase inhibitor herbicides is the main alternative for the control of this species, but it has not been satisfactory in some places, thus causing suspicion of resistance to this action mechanism. Thus, the objective of this paper was to evaluate the occurrence and geographic distribution of ryegrass biotypes that are resistant to the clethodim herbicide in the state of Rio Grande do Sul. For that, seeds of ryegrass plants that survived the application of clethodim were collected in crops from the north region of RS, summing up to a total of 152 samples from 72 cities. The biotypes were submitted to the application of 120 g i.a. ha-1 (maximum registered dose) and 60 g i.a. ha-1 de clethodim (half the maximum registered dose). According to the results, among the samples of ryegrass seeds collected, there were no biotypes resistant to the clethodim herbicide when the maximum registered dose was applied and in the stage of three to four leaves. However, there were biotypes with lower susceptibility that survived half the maximum registered dose. RESUMO O azevém é uma planta daninha de ciclo anual presente em lavouras de inverno, em pomares e vinhedos da região Sul do Brasil. A espécie normalmente é controlada pelo herbicida glyphosate, porém o uso continuado desse produto selecionou biótipos resistentes. O uso de herbicidas inibidores da ACCase é a principal alternativa para o controle dessa espécie, o qual não tem sido satisfatório em alguns locais, provocando a suspeita da ocorrência de resistência a esse mecanismo de ação. Assim, o objetivo deste trabalho foi avaliar a ocorrência e distribuição geográfica de biótipos de azevém resistente ao herbicida clethodim no Estado do Rio Grande do Sul. Para isso, sementes de plantas de azevém que sobreviveram a aplicações de clethodim foram coletadas em lavouras da região norte do RS, totalizando 152 amostras de 72 municípios. Os biótipos foram submetidos à aplicação de 120 g i.a. ha-1 (dose máxima de registro) e 60 g i.a. ha-1 de clethodim (metade da máxima dose de registro). De acordo com os resultados, entre a amostras de sementes de azevém coletadas não foram encontrados biótipos resistentes ao herbicida clethodim quando aplicada a máxima dose de registro e no estádio de três a quatro folhas. No entanto, observaram-se biótipos com menor suscetibilidade, que sobreviveram à metade da máxima dose de registro.
- Published
- 2016
127. Expression of genes in cultivated rice and weedy rice in competition
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C. Oliveira, Leandro Vargas, Embrapa Wheat, Daiane de Pinho Benemann, Dirceu Agostinetto, and Marcos Andre Nohato
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0106 biological sciences ,0301 basic medicine ,media_common.quotation_subject ,Nitrogen assimilation ,Red rice ,food and beverages ,Plant Science ,Interspecific competition ,Biology ,01 natural sciences ,Competition (biology) ,Intraspecific competition ,03 medical and health sciences ,030104 developmental biology ,Botany ,Gene expression ,Agronomy and Crop Science ,Gene ,010606 plant biology & botany ,media_common ,Weedy rice - Abstract
The competition for resources such as light and nitrogen between red rice and cultivated rice can trigger responses in plants that interfere with growth and productivity as well as the expression of genes related to competition-induced stress. Due to its sensitivity, accuracy, and specificity, real-time reverse transcription PCR (RT-qPCR) is an important technique for analyzing differences in gene expression. In this study, we quantified the relative expression levels of genes involved in nitrogen assimilation (OsAMTs, OsGS2 and OsNADH-GOGAT2) and light capture (OsPIL1, OsCRY2 and OsCAB1) in cultivated and red rice in competition under different concentrations of nitrogen (0, 120 and 240 kg ha -1 of nitrogen). Interspecific competition in rice increased the expression of certain genes responsible for assimilating nitrogen (OsNADH-GOGAT2 and OsAMT3;1), and intraspecific competition in red rice also increased the expression of OsGS2. With the interspecific competition, both rice and red rice exhibited increased expression of genes responsible for capturing light, such as OsCRY2 and OsCAB1. With intraspecific competition, red rice showed increased OsPIL1 expression. Additionally, higher doses of nitrogen increased the expression of genes responsible for assimilating nitrogen and capturing light in both cultivated and wild rice species.
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- 2016
128. Resistance characterization of Italian ryegrass (Lolium multiflorum) biotypes to clethodim herbicide
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J. D. da S. Gomes, S. R. Piessanti, Leandro Vargas, Dirceu Agostinetto, T. Schneider, and Ana Claudia Langaro
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0106 biological sciences ,education.field_of_study ,Piperonyl butoxide ,Resistance (ecology) ,biology ,Population ,food and beverages ,04 agricultural and veterinary sciences ,Lolium multiflorum ,biology.organism_classification ,01 natural sciences ,Horticulture ,chemistry.chemical_compound ,chemistry ,Acetyl-coenzyme A carboxylase ,040103 agronomy & agriculture ,0401 agriculture, forestry, and fisheries ,Acetyl coenzyme ,Dry matter ,General Agricultural and Biological Sciences ,education ,Weed ,010606 plant biology & botany - Abstract
The objective of this study is to determine the dose required to control 50% population (C50) and to reduce 50% dry matter production (GR50) of resistant biotypes of ryegrass in comparison to that of a susceptible biotype as well as to evaluate the mechanism of resistance by cyt-P450 inhibitor application. The study was conducted in a greenhouse in Rio Grande do Sul, Brazil on plants that survived clethodim herbicide application, which were suspected of possessing resistance. For plants surviving field application, the biotypes were 50% controlled with herbicide dose of 28.4- and 29.5-times greater compared to that of susceptible biotypes; 50% of dry matter reduction occurred with doses of 540- and 574-times greater than the susceptibility dose of a biotype, since the dose required to reduce 50% of susceptible biotype was 0.2 g a.i. ha-1. The biotypes showed metabolism of clethodim herbicide as regards the inhibition by piperonyl butoxide, indicating that metabolism is the probable cause of control failures in the field. Key words: Lolium multiflorum, acetyl coenzyme A carboxilase, weed, mechanism of resistance; metabolization.
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- 2016
129. Transcriptomic Analysis Identifies New Non-Target Site Glyphosate-Resistance Genes in Conyza bonariensis
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Joanei Cechin, Vanessa Galli, Frederico Schmitt Kremer, Leandro Vargas, C. Neal Stewart, Luciano Carlos da Maia, Reginald J. Millwood, Yongil Yang, Daiane de Pinho Benemann, Cristiano Piasecki, Dirceu Agostinetto, CRISTIANO PIASECKI, YONGIL YANG, DAIANE P. BENEMANN, FREDERICO S. KREMER, VANESSA GALLI, REGINALD J. MILLWOOD, JOANEI CECHIN, DIRCEU AGOSTINETTO, LUCIANO C. MAIA, LEANDRO VARGAS, CNPT, and C. NEAL STEWART JR.
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0106 biological sciences ,Glyphosate ,Candidate gene ,ATP-binding cassette transporter ,RNA-Seq ,Plant Science ,hairy fleabane ,01 natural sciences ,Article ,Transcriptome ,Superoxide dismutase ,03 medical and health sciences ,lcsh:Botany ,Buva ,Erva Daninha ,herbicide resistance ,Gene expression ,differential gene expression ,Gene ,Ecology, Evolution, Behavior and Systematics ,030304 developmental biology ,Genetics ,0303 health sciences ,Ecology ,biology ,herbicide metabolization ,lcsh:QK1-989 ,Herbicide resistance ,Herbicida ,Conyza bonariensis ,biology.protein ,non-target-site resistance (NTSR) ,next-generation sequencing ,Weeds ,Functional genomics ,010606 plant biology & botany - Abstract
Conyza bonariensis (hairy fleabane) is one of the most problematic and widespread glyphosate-resistant weeds in the world. This highly competitive weed species significantly interferes with crop growth and substantially decreases crop yield. Despite its agricultural importance, the molecular mechanisms of glyphosate resistance are still unknown. The present RNA-Seq study was performed with the goal of identifying differentially expressed candidate transcripts (genes) related to metabolism-based non-target site glyphosate resistance in C. bonariensis. The whole-transcriptome was de novo assembled from glyphosate-resistant and -sensitive biotypes of C. bonariensis from Southern Brazil. The RNA was extracted from untreated and glyphosate-treated plants at several timepoints up to 288 h after treatment in both biotypes. The transcriptome assembly produced 90,124 contigs with an average length of 777 bp and N50 of 1118 bp. In response to glyphosate treatment, differential gene expression analysis was performed on glyphosate-resistant and -sensitive biotypes. A total of 9622 genes were differentially expressed as a response to glyphosate treatment in both biotypes, 4297 (44.6%) being up- and 5325 (55.4%) down-regulated. The resistant biotype presented 1770 up- and 2333 down-regulated genes while the sensitive biotype had 2335 and 2800 up- and down-regulated genes, respectively. Among them, 974 up- and 1290 down-regulated genes were co-expressed in both biotypes. In the present work, we identified 41 new candidate target genes from five families related to herbicide transport and metabolism: 19 ABC transporters, 10 CYP450s, one glutathione S-transferase (GST), five glycosyltransferases (GT), and six genes related to antioxidant enzyme catalase (CAT), peroxidase (POD), and superoxide dismutase (SOD). The candidate genes may participate in metabolic-based glyphosate resistance via oxidation, conjugation, transport, and degradation, plus antioxidation. One or more of these genes might &lsquo, rescue&rsquo, resistant plants from irreversible damage after glyphosate treatment. The 41 target genes we report in the present study may inform further functional genomics studies, including gene editing approaches to elucidate glyphosate-resistance mechanisms in C. bonariensis.
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- 2019
130. Dose-response curves of Lolium multiflorum biotypes resistant and susceptible to clethodim
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D.S. Fraga, Leandro Vargas, Franciele Mariani, T.V. Duarte, B.M. Silva, Dirceu Agostinetto, LEANDRO VARGAS, CNPT, UFPel, and UFPel.
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ryegrass ,cyclohexanodiones ,herbicide resistance ,QH301-705.5 ,Physiology ,Plant Science ,Biochemistry ,chemistry.chemical_compound ,Shoot dry weight ,Biology (General) ,Ciclohexanodionas ,biology ,Resistência a herbicidas ,Botany ,food and beverages ,Azevém ,Lolium multiflorum ,Cyclohexanodiones ,biology.organism_classification ,Dose–response relationship ,Agronomy ,chemistry ,QK1-989 ,Glyphosate ,Chemical control ,Agronomy and Crop Science ,After treatment - Abstract
Chemical control with herbicides, especially glyphosate, is the main method used to control ryegrass. However, the repeated use of glyphosate has selected resistant ryegrass biotypes. Thus, the ACCase inhibitor herbicides have become the main alternative to control glyphosate-resistant biotypes, being widely used by farmers in Rio Grande do Sul. Repeated use of ACCase inhibitors, in turn, have selected ryegrass biotypes resistant to this herbicide mechanism. Thus, the objective of this study was to evaluate the response of ryegrass biotypes to different clethodim rates by dose-response curves. Increasing doses (0, 12, 24, 48, 72, 96, 144 and 192 g a.i. ha-1) of the herbicide clethodim were applied at the 3-4 ryegrass leaf stage. The variables control at 14 and 28 days after treatment (DAT) and shoot dry weight were evaluated. The data were fitted by nonlinear regression log-logistic and C50 and GR50 were calculated based on the equation. The resistance factor was obtained by the ratio of C50 or GR50 of the resistant biotype by matching the susceptible biotype. Based on the equation parameters, the doses of GR50 64.7 and 234.5 g a.i. ha-1 clethodim and C50 11.2 and 172.1 g a.i. ha-1 clethodim were obtained, at 28 DAT for the susceptible and resistant biotypes, respectively. The ryegrass biotype denominated Cotril is resistant to clethodim, being controlled with a dose 15.3 times greater than that of the susceptible biotype, and a 50% reduction of this biotype occurs with a dose 3.62 times higher than that of the susceptible one.
- Published
- 2013
131. Valor adaptativo de biótipos de azevém com resistência de nível baixo e suscetível ao herbicida fluazifop e habilidade competitiva com a cultura do trigo
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Leandro Vargas, D.S. Fraga, Nohatto, Dirceu Agostinetto, M.T. Holz, L. Thürmer, UFPel, LEANDRO VARGAS, CNPT, and UFPel.
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Trigo ,Physiology ,QH301-705.5 ,media_common.quotation_subject ,competição ,Greenhouse ,Biomass ,Plant Science ,Biology ,Biochemistry ,Competition (biology) ,Crop ,Lolium multiflorum ,Cultivar ,Biology (General) ,Azevém ,media_common ,Resistance (ecology) ,fungi ,Botany ,food and beverages ,planta daninha ,Agronomy ,QK1-989 ,Shoot ,Herbicida ,Weed ,Agronomy and Crop Science ,competition ,weed - Abstract
Ryegrass is the main weed in wheat crop, causing yield loss due to competition by environmental resources. The objectives of this study were to estimate the fitness cost of ryegrass biotypes with low-level resistance and susceptible to fluazifop and to investigate the relative competitive ability of these biotypes between themselves and against the crop. Thus, fitness cost and competitive ability experiments were conducted under greenhouse conditions. For the fitness cost experiments, the low-level resistant ryegrass biotypes and those susceptible to fluazifop were used. For competitive ability, the treatments were arranged in a replacement series, with five proportions of the wheat cultivar FUNDACEP Horizonte and the low-level resistant and susceptible ryegrass biotypes 100:0, 75:25, 50:50, 25:75 and 0:100. Competitive analysis was carried out through diagrams applied to the replacement experiments and use of relative competitiveness indices. Variables evaluated were plant height, in the fitness cost experiment, and leaf area and shoot dry biomass in both experiments. The ryegrass biotypes show overall similar fitness cost and competitive ability. The wheat cultivar FUNDACEP Horizonte is superior in competitive ability to the ryegrass biotype with low-level resistance and equivalent to the susceptible biotype. O azevém é a principal planta daninha da cultura do trigo, a qual contribui para a perda de produtividade devido à competição exercida por recursos do ambiente. Os objetivos deste trabalho foram estimar o valor adaptativo de biótipos de azevém com resistência de nível baixo e suscetível ao herbicida fluazifop e investigar a habilidade competitiva relativa desses biótipos entre si e com a cultura do trigo. Para isso, foram realizados experimentos de valor adaptativo e habilidade competitiva em casa de vegetação. Para valor adaptativo, utilizaram-se biótipos de azevém com resistência de nível baixo e suscetível ao herbicida fluazifop. Quanto à habilidade competitiva, os tratamentos foram arranjados em série de substituição, constituindo-se de cinco proporções de plantas de trigo cultivar FUNDACEP Horizonte e biótipos de azevém com resistência de nível baixo e suscetível: 100:0, 75:25, 50:50, 25:75 e 0:100. A análise da competitividade foi efetuada por meio de diagramas aplicados a experimentos substitutivos e uso de índices de competitividade relativa. As variáveis avaliadas foram estatura, no experimento de valor adaptativo, e área foliar e matéria seca da parte aérea, em ambos. Os biótipos de azevém apresentam, em geral, valor adaptativo e habilidade competitiva similares. O trigo cultivar FUNDACEP Horizonte apresenta habilidade competitiva superior à do biótipo de azevém com resistência de nível baixo e equivalente à do suscetível.
- Published
- 2013
132. MRAC and MPC Controllers for Load Application System of the Accelerated Testing Equipment of Pavements
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Juan Sebastian Useche Castelblanco, German Leandro Vargas Fonseca, and Oscar Javier Reyes Ortiz
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Lyapunov function ,0209 industrial biotechnology ,Interconnection ,General Computer Science ,Computer science ,Scale (chemistry) ,Work (physics) ,Control (management) ,0211 other engineering and technologies ,General Engineering ,Control engineering ,02 engineering and technology ,symbols.namesake ,Model predictive control ,020901 industrial engineering & automation ,Control theory ,021105 building & construction ,symbols ,General Agricultural and Biological Sciences ,Reference model - Abstract
For the study of pavement structures, different methodologies and devices have been used and those have been modified and modernized. The development of these routes directly impacts the social and economic development of the different regions. Through the roads, the interconnection between different points is allowed, and the resources that need to be invested for its construction are high. Trends show real-scale studies to determine real operating parameters that allow improving design processes. For this reason, test devices have been developed that simulating real operating conditions, but these machines require robust and efficient control. Adaptive and predictive controls are the most used in industrial processes, where it is necessary to reduce performance and operation costs—obtaining smooth transitions in the control signal, especially when techniques are used with follow-up to reference models. This document shows the design of the MRAC (Adaptive Reference Control Model) and MPC (Predictive Control Model) controller applied to a hydraulic loading system for real-scale pavement test equipment. The mathematical development of the plant and the controllers is presented, along with its implementation, simulation, and analysis. The main objective of this work is to verify the effectiveness of these controllers for this type of real scale system since due to the number of variables that affect these devices and the complexity of the study material.
- Published
- 2020
133. Physical, Physiological and Sanitary Quality of Canola Seeds After the Application of Maturing Herbicides
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Leandro Vargas, César Tiago Forte, Daiani Brandler, Leandro Galon, Rodrigo José Tonin, Josiel Ricardo Toni, Felipe Bianchessi, and Thalita Pedrozo Pilla
- Subjects
food.ingredient ,Saflufenacil ,Randomized block design ,Biology ,Diquat ,chemistry.chemical_compound ,food ,Paraquat ,chemistry ,Agronomy ,Glufosinate ,Glyphosate ,Sanity testing ,Canola - Abstract
The use of herbicides to anticipate harvesting in species with easy seed dehiscence may be an alternative to avoid maturation losses. However, the appropriate time for herbicide application is extremely important as it prevents the seeds from remaining in the field for long periods. The objective of this study was to evaluate the efficiency of the application of maturing herbicides in two distinct seasons, and their effects on the physical, physiological, and sanitary quality of canola seeds. A randomized block experimental design arranged in a factorial scheme (herbicide x season + control) with four replications was used. Hybrid 50 canola plants were matured with the herbicides: glufosinate, paraquat, glyphosate, diquat, saflufenacil, 2,4-D, and paraquat + diuron twice during the crop cycle, G3 and G4, and two controls without application for each epoch, with the first being harvested the day of product application, and the second kept in the field until the final crop cycle. Analyses of one thousand seed weight, electrical conductivity, emergence speed index, and a sanity test were performed. The application of maturing herbicides to canola increases the one thousand seed weight and rate of emergence speed. At the same time, it increases electrical conductivity and the incidence of fungi. Plants that remained in the field until the end of the crop cycle and did not receive herbicide application resulted in higher quality seeds. The most appropriate moment to apply maturation herbicides to canola is in the G4 season.
- Published
- 2020
134. Interferência do milho voluntário na soja resistente ao glifosato e controle químico em diferentes estádios fenológicos
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Vinicius Zimmer, Joanei Cechin, Leandro Vargas, Dirceu Agostinetto, and Mariane Pertile
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Glycine max ,QH301-705.5 ,glycine max ,Biology ,Interference (genetic) ,Zea mays ,zea mays ,chemistry.chemical_compound ,Alternative herbicides ,Biology (General) ,Volunteer ,Competition ,Phenology ,Agricultural Sciences ,Economic threshold level ,food and beverages ,Agriculture ,economic threshold level ,Agronomy ,chemistry ,Glyphosate ,alternative herbicides ,General Agricultural and Biological Sciences ,Chemical control ,competition - Abstract
The successive use of Roundup Ready crops may difficult the management of volunteer plants originated from seed losses during harvest. In soybean, volunteer corn plants can exhibit higher interference and cause reduce yield depending on their density. The aim of this study was to quantify the economic threshold level (ETL) in soybean as a function of the competition of volunteer corn and to evaluate the chemical control in different phenological stages of development. The ETL and chemical control experiments were conducted in the field, under completely randomized and randomized block designs with one and three replicates, respectively. The variables analyzed were yield and ETL as functions of the competition of different volunteer corn populations (control, 1, 2, 4, 6, 8, 10, 12, 16, 20, 24 and 32 plants m-2) and the chemical control with acetyl coenzyme-A carboxylase (ACCase) inhibitor herbicides alone or mixed with glyphosate in different phenological stages of development (V2-V3, V4-V5 and V6-V8) that were evaluated at seven, 14 and 21 days after application (DAA). The results showed higher competitive potential of volunteer corn in which the presence of one plant m-2 reduces the soybean yield in 17%. The ETL ranged from 0.14 to 0.78 plants m-2 and the control of volunteer corn must be carried out in low populations. The use of ACCase inhibitors herbicides alone or mixed with glyphosate demonstrated greater than 85% control in the V2-V3 phenological stage independent of the period evaluated. The effectiveness of all herbicides decreased with application delay with a control level above 87%, in the V6-V8 phenological stage, obtained only for fluazifop and haloxyfop herbicides alone or in mixed with glyphosate at 14 and 21 days after application. O uso sucessivo de culturas “Roundup Ready” pode dificultar o manejo de plantas voluntárias originadas de sementes perdidas durante a colheita. Na soja, plantas de milho voluntário podem apresentar elevadainterferência e causar redução da produtividade dependendo da sua densidade. O objetivo do estudo foi quantificar o nível de dano econômico (NDE) na soja em função da competição de milho voluntário e avaliar o controle químico em diferentes estádios fenológicos de desenvolvimento. Os experimentos de NDE e controle químico foram conduzidos a campo, em delineamento inteiramente e blocos casualizados com uma e três repetições, respectivamente. As variáveis analisadas foram a produtividade e o NDE em função da competição das diferentes populações de milho voluntário (zero; um; dois; quatro; seis; oito; 10; 12; 16; 20; 24 e 32 plantas m-²) e o controle químico com herbicidas inibidores da enzima acetil CoA carboxilase (ACCase) isolados ou misturados com o glifosato em diferentes estádios fenológicos de desenvolvimento (V2-V3; V4-V5 e V6-V8) que foram avaliados aos sete, 14 e 21 dias após a aplicação (DAA). Os resultados demonstraram maior potencial competitivo do milho voluntário onde a presença de uma planta m-2 reduziu a produtividade da soja em 17%. O NDE variou de 0,14 a 0,78 plantas m-2 e o controle do milho voluntário deve ser realizado em populações baixas. O uso de herbicidas inibidores da ACCase isolados ou misturados com o glifosato proporcionaram controle superior 85% no estádio fenológico V2-V3 independente do período avaliado. A eficácia de todos os herbicidas decresceu com o atraso da aplicação com um nível de controle acima de 87%, no estádio fenológico V6-V8, obtido apenas para os herbicidas fluazifope e haloxifope isolado ou em mistura com o glifosato aos 14 e 21 dias após aplicação.
- Published
- 2018
135. CARACTERIZAÇÃO MORFOANATÔMICA, CONTAGEM CROMOSSÔMICA E VIABILIDADE POLÍNICA DE BIÓTIPOS DE AZEVÉM SUSCETÍVEL E RESISTENTES AO HERBICIDA GLYPHOSATE
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Leandro Vargas, J. A. Fernando, Q. Ruchel, Dirceu Agostinetto, Vera Lucia Bobrowski, and R. Lüdtke
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Physiology ,QH301-705.5 ,Botany ,Plant Science ,Poaceae ,Biochemistry ,anatomia ,morfologia ,Lolium multiflorum ,QK1-989 ,cromossomos ,Biology (General) ,Agronomy and Crop Science - Abstract
RESUMOO azevém é uma planta daninha de ciclo anual, encontrada em praticamente todas as lavouras de inverno, em pomares e vinhedos da região Sul do Brasil. A espécie é normalmente controlada pelo herbicida glyphosate, no entanto, o uso continuado desse produto selecionou biótipos resistentes. Diferenças na suscetibilidade do azevém a herbicidas têm sido atribuídas a características morfológicas, anatômicas e genéticas das plantas. Os objetivos deste trabalho foram realizar a caracterização morfoanatômica, adequar metodologia para a análise citológica de cromossomos e indicar corantes para testes de viabilidade polínica de biótipos de azevém suscetível e resistentes ao herbicida glyphosate. As sementes dos biótipos de azevém suspeitos de resistência provieram do município de São Valentin, RS (SVA 1 e SVA 4), e Passo Fundo, RS (PFU 5), e as do biótipo conhecidamente suscetível (SVA 2), de São Valentin. Os biótipos de azevém estudados que apresentam resistência ao herbicida glyphosate não podem ser diferenciados do biótipo suscetível através de aspectos morfológicos, não existindo diferenças anatômicas de folha e raiz que evidenciem possibilidade da absorção diferencial do herbicida glyphosate entre os biótipos de azevém. A metodologia para a análise citológica dos biótipos de azevém merece adequações para melhor nitidez dos cromossomos, podendo-se aumentar o tempo de hidrólise e de exposição ao agente antimitótico utilizado neste trabalho, bem como testar outros agentes. Todos os corantes apresentaram bom desempenho na determinação da viabilidade polínica frente aos biótipos avaliados, exceto o azul de tripan, que subestimou os resultados.
- Published
- 2015
136. Effect of glyphosate on the physiological parameters of horseweed
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Leandro Vargas, Geraldo Chavarria, Franciele Mariani, Dirceu Agostinetto, Fernando Machado dos Santos, Pedro Jacob Christoffoleti, and M.B. Matallo
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ATP synthase ,musculoskeletal, neural, and ocular physiology ,Shikimic acid ,Biology ,Photosynthesis ,Phosphate ,chemistry.chemical_compound ,Horticulture ,nervous system ,chemistry ,Agronomy ,Glyphosate ,Herbicide resistance ,biology.protein ,sense organs ,skin and connective tissue diseases ,General Agricultural and Biological Sciences - Abstract
Resumen en: The aim of this study was to determine changes in the photosynthetic process and the inhibition of 5-enolpyruvylshikimate-3- phosphate synthase (EPSPs) b...
- Published
- 2014
137. Competitive ability of barley cultivars against ryegrass
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Paulo Roberto Ribeiro Rocha, Adinan Alves da Silva, S.P Tironi, Edimar Rodrigues Soares, A.F. Silva, Leandro Galon, Germani Concenço, Francisco A. Ferreira, Evander Alves Ferreira, Leandro Vargas, E. Minella, GERMANI CONCENCO, CPAO, LEANDRO VARGAS, CNPT, and EUCLYDES MINELLA, CNPT.
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Lolium Multiflorum ,Physiology ,Randomized block design ,Greenhouse ,morphophysiological characteristics ,Plant Science ,Biology ,Weed control ,características morfofisiológicas ,Biochemistry ,winter cereals ,cereais de inverno ,Agronomy ,Dry weight ,Lolium multiflorum ,Shoot ,Management methods ,Weed ,Agronomy and Crop Science ,Características morfofisiológicas ,Hordeum vulgare - Abstract
A determinação da habilidade competitiva de cultivares de cevada com plantas daninhas torna-se relevante para a adoção do método de manejo cultural; desse modo, podemse diminuir os custos de produção, bem como os impactos ambientais causados por outros métodos de manejo, como o químico. Este trabalho comparou as habilidades competitivas relativas de três cultivares de cevada e um biótipo de azevém. Foram realizados experimentos em casa de vegetação na estação de crescimento 2008/09, utilizando-se delineamento experimental de blocos casualizados, com quatro repetições. Os tratamentos foram arranjados em série de substituição e constituíram-se de cinco proporções de plantas de cevada e do azevém competidor com a cultura: 100:0, 75:25, 50:50, 25:75 e 0:100. A cevada foi representada pelos cultivares BRS Greta, BRS Elis e BRS 225, e o competidor, pelo azevém. A análise da competitividade foi efetuada por meio de diagramas aplicados a experimentos substitutivos, mais uso de índices de competitividade relativa. As variáveis estudadas foram: afilhamento, estatura, área foliar e massa da matéria seca da parte aérea das plantas. O azevém afetou o afilhamento, a área foliar e a massa da matéria seca da parte aérea de plantas dos cultivares de cevada BRS Greta, BRS Elis e BRS 225, demonstrando grande habilidade competitiva com a cultura pelos recursos disponíveis no meio. Entre os cultivares de cevada avaliados, BRS Elis foi o mais competitivo na presença do azevém, que é uma das espécies daninhas que necessitam de controle mesmo quando presente em baixas proporções na cultura da cevada. Characterization of the competitive ability of barley varieties against weed species is relevant for the adoption of the cultural method of weed control; thus, it is possible to reduce both the production costs and environmental impacts caused by other management methods, including the use of chemicals. This work assessed the competitive ability of barley varieties against ryegrass. Trials were installed under greenhouse conditions at the 2008/2009 cropping season, in a completely randomized block design, with four replications. Treatments were arranged in a substitution series design constituted by five proportions of plants of both species: 100:0; 75:25; 50:50; 25:75; and 0:100. Barley varieties BRS Greta, BRS Elis and BRS 225 were tested against ryegrass as the competitor. The competitive analysis was carried out through diagrams applied to the substitutive design, plus determination of relative competitiveness indexes. Plant height, tillering, leaf area and shoot dry mass were evaluated. The presence of ryegrass reduced tillering, leaf area and dry mass accumulation for all varieties of barley tested, showing to be an aggressive competitor. Among the barley varieties tested, BRS Elis showed the highest competitive ability against ryegrass. Ryegrass requires the adoption of control techniques even when present at low proportions in the field.
- Published
- 2011
138. Competição de trigo com azevém em função de épocas de aplicação e doses de nitrogênio
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Dirceu Agostinetto, Diecson Ruy Orsolin da Silva, Leandro Vargas, C.E. Schaedler, J.M. Paula, UFPEL, and LEANDRO VARGAS, CNPT.
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Planta daninha ,plantas daninhas ,Lolium Multiflorum ,Physiology ,Triticum aestivum ,interferência ,Plant Science ,Triticum Aestivum ,Agronomy and Crop Science ,Biochemistry - Abstract
O potencial de produtividade da cultura do trigo é limitado pela competição exercida pelas plantas daninhas, especialmente pelos recursos luz, água e nutrientes. Em sistemas de produção, a disponibilidade de nitrogênio (N) quase sempre é limitante, influenciando o crescimento da planta mais do que qualquer outro nutriente. O objetivo deste trabalho foi avaliar variáveis morfológicas e componentes da produtividade da cultura do trigo em competição com azevém, em função de épocas de aplicação e doses de N. Os tratamentos foram dispostos em esquema fatorial (2 x 3 x 5), em que o primeiro fator constou de condição de competição (ausência e presença de azevém), o segundo testou épocas de aplicação de N (100% aplicado no início do afilhamento; 50% no início do afilhamento e 50% no início da diferenciação da espiga (IDE); e 100% no IDE) e o terceiro avaliou doses de N (0, 40, 80, 120 e 160 kg ha-1), na forma de ureia aplicada a lanço. As variáveis analisadas foram: área foliar (AF), massa seca da parte aérea (MSPA), número de afilhos (NA), número de colmos (NC), teor de N da cultura (TN), número de grãos por espigueta (NGES), número de grãos por espiga (NGE), número de espiguetas por espiga (NESE), produtividade biológica (PB), massa média de mil grãos (MMG) e produtividade de grãos (P). O azevém compete com o trigo pelo recurso N, reduzindo a AF, MSPA, NA, NC, TN, NGES, NGE, NESE, PB, MMG e P da cultura. A aplicação do N no início do afilhamento ou fracionada, nas duas doses mais elevadas, aumenta a AF e MSPA. O aumento da dose de N incrementa o TN na cultura do trigo, independentemente da presença ou ausência do competidor. A aplicação de N no IDE ou o incremento da dose de N aumenta o NGES e NGE.
- Published
- 2011
139. Competitive ability between biotypes of Cyperus difformis L. resistant or susceptible to ALS-inhibitor herbicide and those with flooded rice
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Lisiane Camponogara Fontana, Taísa Dal Magro, C.E. Schaedler, Dirceu Agostinetto, Leandro Vargas, Taísa Dal Magro, UFPEL, Carlos Eduardo Schaedler, UFPEL, Lisiane Camponogara Fontana, UFPEL, Dirceu Agostinetto, UFPEL, and LEANDRO VARGAS, CNPT.
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Oryza Sativa ,Oryza sativa ,Materials Science (miscellaneous) ,competição ,Interspecific competition ,Biology ,biology.organism_classification ,lcsh:S1-972 ,série de substituição ,Intraspecific competition ,Horticulture ,Dry weight ,Cyperus difformis ,Arroz ,Competição ,Herbicida ,Shoot ,Botany ,replacement series ,Cultivar ,lcsh:Agriculture (General) ,General Agricultural and Biological Sciences ,competition ,Completely randomized design - Abstract
Em biótipos de plantas daninhas resistentes a herbicidas pode haver menor habilidade competitiva, comparativamente aos biótipos suscetíveis. O objetivo da pesquisa foi investigar a habilidade competitiva entre biótipos de Cyperus difformis L. resistente ou suscetível a herbicidas e destes com arroz irrigado. Foram realizados quatro experimentos em casa de vegetação, em 2007 e 2008, em delineamento inteiramente casualizado, com quatro repetições, sendo os tratamentos do primeiro arranjado em série aditiva e dos demais arranjados em série de substituição. Em cada experimento, as proporções entre biótipos de C. difformis resistente e suscetível e destes com arroz foram de 100:0, 75:25, 50:50, 25:75 e 100:0%, com população total de 1060 plantas m-2. As variáveis avaliadas foram área foliar, estatura e matéria seca da parte aérea. A análise da competitividade foi realizada por aplicação de diagramas e interpretações dos índices de competitividade. Biótipos de C. difformis resistente e suscetível a herbicidas inibidores de ALS, em geral, possuem habilidade competitiva equivalente; a cultura do arroz, com a cultivar BRS Querência, tem habilidade competitiva superior a C. difformis resistente ou suscetível a herbicidas inibidores de ALS; para a cultura do arroz, a competição intraespecífica é mais importante, enquanto para C. difformis resistente ou suscetível a herbicidas inibidores de ALS, a mais importante é a competição interespecífica. Biotypes of weeds resistant to herbicides may have lower competitive ability compared to susceptible biotypes. The objective of the study was to investigate the relative competitive ability between biotypes of Cyperus difformis L. resistant or susceptible to ALS-inhibitor herbicides and with rice. Four experiments were carried out under greenhouse, in a completely randomized design with four replications, in 2007 and 2008. Treatments were arranged in additive series and replacement series assay. In each series, the proportion among C. difformis resistant and susceptible plants related to rice were: 100:0, 75:25, 50:50, 25:75 and 100:0%, always with a total population of 1060 plants m-2. Leaf area, plant height and shoot dry mass were evaluated. Competitiveness statistical analysis consisted in applying diagrams to the replacement series and alternative interpretations of the competitiveness indexes. In general, biotypes C. difformis resistant and susceptible to ALS-inhibitors herbicides have equivalent competitive ability; the rice cultivar BRS Querência has superior competitive ability in relation to C. difformis resistant or susceptible to ALS-inhibitors herbicides; and for rice, the intraspecific competition is more important, while for C. difformis resistant or susceptible to ALS-inhibitors herbicides, the most important is the interspecific competition.
- Published
- 2011
140. Mutação da Trp-574-Leu do gene ALS confere resistência de biótipos de nabo ao herbicida iodosulfurom e imazetapir
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Joanei Cechin, Franciele Mariani, Fabiane Pinto Lamego, Leandro Vargas, Dirceu Agostinetto, and Taísa Dal Magro
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Piperonyl butoxide ,Agriculture (General) ,Fitossanidade ,010501 environmental sciences ,Biology ,Gene mutation ,01 natural sciences ,S1-972 ,Microbiology ,chemistry.chemical_compound ,mecanismo de resistência ,ALS enzyme activity ,gene mutation ,0105 earth and related environmental sciences ,chemistry.chemical_classification ,Genetics ,Acetolactate synthase ,Tryptophan ,mechanism of resistence ,Raphanus sativus ,metabolismo ,04 agricultural and veterinary sciences ,atividade da enzima ALS ,Enzyme assay ,Enzyme ,Herbologia e Resistência de plantas daninhas ,chemistry ,040103 agronomy & agriculture ,biology.protein ,0401 agriculture, forestry, and fisheries ,Malathion ,mutação gênica ,Leucine ,Agronomy and Crop Science ,metabolism - Abstract
Acetolactate synthase inhibitors are the main group of herbicides used in winter crops in Southern Brazil where their intensive use has selected for herbicide-resistant biotypes of radish. The resistance affects the efficacy of herbicides, and identifying the resistance mechanism involved is important for defining management strategies. The aim of this study was to elucidate the resistance mechanism of radish biotypes by quantifying the enzyme activity, ALS gene sequencing and evaluating the response of biotypes to iodosulfuron and imazethapyr herbicide application after treatment with a cytochrome P450 monooxygenase inhibitor. The susceptible (B1) and resistant (B4 and B13) biotypes were from wheat fields in the Northwest of Rio Grande do Sul State. The results demonstrated that the enzyme affinity for the substrate (KM) was not affected in biotypes B4 and B13 but that the Vmax of the resistant biotypes was higher than that of biotype B1. The resistant biotypes showed no differential metabolic response to iodosulfuron and imazethapyr herbicides when inhibited by malathion and piperonyl butoxide. However, gene sequencing of ALS showed a mutation at position 574, with an amino acid substitution of tryptophan for leucine (Trp-574-Leu) in resistant biotypes. RESUMO. Os inibidores da acetolactato sintase são o principal grupo de herbicidas usados em culturas de inverno do Sul do Brasil onde seu uso intenso selecionou biótipos resistentes de nabo. A resistência afeta a eficácia dos herbicidas, e a identificação do mecanismo de resistência envolvido é importante na definição de estratégias de manejo. O objetivo deste estudo foi elucidar o mecanismo de resistência em biótipos de nabo através da quantificação da atividade da enzima, sequenciamento do gene ALS e avaliar a resposta dos biótipos à aplicação do herbicida iodosulfurom e imazetapir após tratamento com inibidores do metabolismo da citocromo P450 monooxigenase. Os biótipos suscetível (B1) e resistentes (B4 e B13) eram de lavouras de trigo da região Noroeste do Estado do Rio Grande do Sul. Os resultados demonstraram que a afinidade da enzima pelo substrato (KM) não foi afetada nos biótipos B4 e B13, porém o Vmax dos biótipos resistentes foi superior quando comparado ao biótipo B1. Os biótipos resistentes não apresentaram resposta metabólica diferencial ao herbicida iodosulfurom e imazetapir quando inibidos pelo malathion e butóxido de piperolina. Entranto, o sequenciamento do gene ALS evidenciou mutação na posição 574 com uma substituição do aminoácido triptofano por leucina (Trp-574-Leu) nos biótipos resistentes.
- Published
- 2017
141. Avaliação ambiental de BTEX (benzeno, tolueno, etilbenzeno, xilenos) e biomarcadores de genotoxicidade em trabalhadores de postos de combustíveis
- Author
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Angélica Cardoso Pereira, Sergio Machado Corrêa, Rita de Cássia Oliveira da Costa Mattos, Frederico Peres, Simone Mitri Nogueira, Marianne Medeiros Tabalipa, Josino Costa Moreira, Antônio Sérgio Almeida Fonseca, Marco Antônio Carneiro Menezes, Vinicio Soares de Castro, Sérgio Rabello Alves, Jucilene Aparecida Vieira, Isabele Campos Costa Amaral, Ariane Leites Larentis, Katia Maria Pinto Guedes de Oliveira, Paula de Novaes Sarcinelli, Leandro Vargas Barreto de Carvalho, Liliane Reis Teixeira, Renato Marçullo Borges, Joyce Neri da Silva Pimentel, and Ubirani Barros Otero
- Subjects
0301 basic medicine ,BTEX ,010501 environmental sciences ,01 natural sciences ,Ethylbenzene ,postos de combustíveis ,03 medical and health sciences ,Human health ,chemistry.chemical_compound ,comet assay ,oxidative stress ,Benzene ,Volume concentration ,0105 earth and related environmental sciences ,ensaio cometa ,lcsh:Public aspects of medicine ,lcsh:RA1-1270 ,General Medicine ,Toluene ,Comet assay ,estresse oxidativo ,saúde ocupacional ,030104 developmental biology ,chemistry ,Environmental chemistry ,occupational health ,Environmental science ,Occupational exposure ,gas stations - Abstract
Resumo Introdução: trabalhadores de postos de combustíveis estão expostos às diversas substâncias químicas presentes no ambiente de trabalho, destacando-se entre elas o benzeno, devido às suas propriedades carcinogênicas. Objetivo: avaliar os danos genotóxicos relacionados à exposição ocupacional ao BTEX (benzeno, tolueno, etilbenzeno, xilenos) em trabalhadores de cinco postos de combustíveis do município do Rio de Janeiro, RJ. Metodologia: foram analisadas concentrações de BTEX no ar; atividades das enzimas catalase e glutationa S-transferase; e ensaio cometa em amostras de sangue total de 97 trabalhadores. Resultados: as concentrações de BTEX estavam dentro dos valores preconizados pela NR 15, incluindo Anexo 13-A. Entretanto, uma oscilação nos resultados de ensaio cometa foi observada entre os trabalhadores dos diferentes postos de combustíveis, principalmente em trabalhadores de postos com menores concentrações de benzeno. Discussão: esse resultado está de acordo com a literatura científica atual, que indica uma curva dose-resposta supralinear para o benzeno, observando-se em baixas concentrações um aumento não linear do risco de leucemia, provavelmente relacionado à maior metabolização do benzeno e à maior produção de seus metabólitos tóxicos nessas concentrações. Conclusão: os resultados deste estudo sugerem que a exposição ao BTEX, mesmo em baixas concentrações, contribui para o risco genotóxico à saúde humana.
- Published
- 2017
142. Avaliação ambiental de BTEX (benzeno, tolueno, etilbenzeno, xilenos) e biomarcadores de genotoxicidade em trabalhadores de postos de combustíveis
- Author
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Amaral, Isabele Campos Costa, Carvalho, Leandro Vargas Barreto de, Pimentel, Joyce Neri da Silva, Pereira, Angélica Cardoso, Vieira, Jucilene Aparecida, Castro, Vinicio Soares de, Borges, Renato Marçullo, Alves, Sérgio Rabello, Nogueira, Simone Mitri, Tabalipa, Marianne de Medeiros, Otero, Ubirani Barros, Oliveira, Katia Maria Pinto Guedes de, Corrêa, Sérgio Machado, Fonseca, Antônio Sérgio Almeida, Moreira, Josino Costa, Peres, Frederico, Teixeira, Liliane Reis, Menezes, Marco Antônio Carneiro, Mattos, Rita de Cássia Oliveira da Costa, Sarcinelli, Paula de Novaes, and Larentis, Ariane Leites
- Subjects
estresse oxidativo ,saúde ocupacional ,ensaio cometa ,comet assay ,occupational health ,oxidative stress ,gas stations ,postos de combustíveis ,BTEX - Abstract
Resumo Introdução: trabalhadores de postos de combustíveis estão expostos às diversas substâncias químicas presentes no ambiente de trabalho, destacando-se entre elas o benzeno, devido às suas propriedades carcinogênicas. Objetivo: avaliar os danos genotóxicos relacionados à exposição ocupacional ao BTEX (benzeno, tolueno, etilbenzeno, xilenos) em trabalhadores de cinco postos de combustíveis do município do Rio de Janeiro, RJ. Metodologia: foram analisadas concentrações de BTEX no ar; atividades das enzimas catalase e glutationa S-transferase; e ensaio cometa em amostras de sangue total de 97 trabalhadores. Resultados: as concentrações de BTEX estavam dentro dos valores preconizados pela NR 15, incluindo Anexo 13-A. Entretanto, uma oscilação nos resultados de ensaio cometa foi observada entre os trabalhadores dos diferentes postos de combustíveis, principalmente em trabalhadores de postos com menores concentrações de benzeno. Discussão: esse resultado está de acordo com a literatura científica atual, que indica uma curva dose-resposta supralinear para o benzeno, observando-se em baixas concentrações um aumento não linear do risco de leucemia, provavelmente relacionado à maior metabolização do benzeno e à maior produção de seus metabólitos tóxicos nessas concentrações. Conclusão: os resultados deste estudo sugerem que a exposição ao BTEX, mesmo em baixas concentrações, contribui para o risco genotóxico à saúde humana. Abstract Introduction: gas station workers are exposed to several chemicals in their workplace, highlighting benzene, due to its carcinogenic properties. Objective: to assess the genotoxic damage related to occupational exposure to BTEX (benzene, toluene, ethylbenzene, xylenes) in workers of five gas stations in Rio de Janeiro, RJ. Methods: analysis of BTEX concentrations in the air were carried out; as well as activities of catalase and glutathione S-transferase; and comet assay in whole blood samples of 97 workers. Results: BTEX levels were within the Brazilian threshold levels recommended by the NR 15, including Annex 13-A. However, an oscillation of the comet assay results was observed among workers of different gas stations, mainly in workers from gas stations with lower concentrations of benzene. Discussion: this result is in accordance with the current international scientific literature that indicates a supralinear exposure-response curve for benzene. In lower concentrations we could observe a high non-linear risk of leukemia, probably due to a greater benzene metabolism and a higher production of its toxic metabolites. Conclusion: the results of this study suggest that exposure to BTEX, even in low concentrations, contributes to genotoxic risk to human health.
- Published
- 2017
143. Sensor Fusion Based on an Integrated Neural Network and Probability Density Function (PDF) Dual Kalman Filter for On-Line Estimation of Vehicle Parameters and States
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Beatriz L. Boada, Vicente Díaz, María Jesús López Boada, Leandro Vargas-Meléndez, and A. Gauchía
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Truck ,0209 industrial biotechnology ,Engineering ,dual Kalman filter ,vehicle dynamics ,probability density function (PDF) truncation ,state estimation ,parameter estimation ,vehicle roll angle ,sensor fusion ,Probability density function ,Vehicle dynamics ,02 engineering and technology ,Biochemistry ,Article ,Analytical Chemistry ,020901 industrial engineering & automation ,Control theory ,0502 economics and business ,Parameter estimation ,Electrical and Electronic Engineering ,Instrumentation ,Ingeniería Mecánica ,Sensor fusion ,050210 logistics & transportation ,business.industry ,Dual Kalman filter ,05 social sciences ,Kalman filter ,Rollover ,Vehicle roll angle ,Atomic and Molecular Physics, and Optics ,Center of gravity ,Electronic stability control ,Global Positioning System ,Probability density function (PDF) truncation ,business ,State estimation - Abstract
Vehicles with a high center of gravity (COG), such as light trucks and heavy vehicles, are prone to rollover. This kind of accident causes nearly 33% of all deaths from passenger vehicle crashes. Nowadays, these vehicles are incorporating roll stability control (RSC) systems to improve their safety. Most of the RSC systems require the vehicle roll angle as a known input variable to predict the lateral load transfer. The vehicle roll angle can be directly measured by a dual antenna global positioning system (GPS), but it is expensive. For this reason, it is important to estimate the vehicle roll angle from sensors installed onboard in current vehicles. On the other hand, the knowledge of the vehicle's parameters values is essential to obtain an accurate vehicle response. Some of vehicle parameters cannot be easily obtained and they can vary over time. In this paper, an algorithm for the simultaneous on-line estimation of vehicle's roll angle and parameters is proposed. This algorithm uses a probability density function (PDF)-based truncation method in combination with a dual Kalman filter (DKF), to guarantee that both vehicle's states and parameters are within bounds that have a physical meaning, using the information obtained from sensors mounted on vehicles. Experimental results show the effectiveness of the proposed algorithm. This work is supported by the Spanish Government through the Project TRA2013-48030-C2-1-R, which is gratefully acknowledged.
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- 2017
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144. Utilização de biomarcadores de genotoxicidade e expressão gênica na avaliação de trabalhadores de postos de combustíveis expostos a vapores de gasolina
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Jamila Alessandra Perini, Eline Simões Gonçalves, Herbert Ary Sisenando, Leiliane Coelho André, Paula de Novaes Sarcinelli, Anna De Falco, Rita de Cássia Oliveira da Costa Mattos, Marcus Vinicius Corrêa dos Santos, Simone Mitri Nogueira, Vinicio Soares de Castro, Ariane Leites Larentis, Leandro Vargas Barreto de Carvalho, Isabele Campos Costa-Amaral, Liliane Reis Teixeira, Josino Costa Moreira, Daniel Valente, Monica Stuck de Oliveira, Cristiane Barata Silva, and Daniela del Rosário Flores Rodrigues
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0301 basic medicine ,Genotoxicidade ,Protein adducts ,010501 environmental sciences ,Bioinformatics ,medicine.disease_cause ,01 natural sciences ,Toxicology ,03 medical and health sciences ,benzene ,expressão gênica ,Medicine ,oxidative stress ,Epigenetics ,Toxicologia ,benzeno ,0105 earth and related environmental sciences ,business.industry ,lcsh:Public aspects of medicine ,lcsh:RA1-1270 ,General Medicine ,occupational exposure ,Comet assay ,estresse oxidativo ,genic expression ,030104 developmental biology ,exposição ocupacional ,Micronucleus test ,Occupational exposure ,business ,Genotoxicity - Abstract
Outra Agência Introdução: a avaliação de uma exposição mensura sua intensidade, frequência e duração, podendo detectar danos precoces que, se ignorados, podem evoluir para um quadro nocivo. Nos campos da saúde ambiental e ocupacional, os biomarcadores de genotoxicidade tem sido largamente utilizados para essa avaliação. Objetivo: identificar, descrever e discutir os principais bioindicadores de genotoxicidade e seu uso conjunto com técnicas de avaliação de expressão gênica em estudos de exposição ocupacional ao benzeno em postos de revenda de combustíveis (PRC). Métodos: revisão bibliográfica de trabalhos publicados entre 1995 e 2015. Resultados: as técnicas identificadas foram: ensaio cometa, estresse oxidativo, micronúcleos, aberrações cromossômicas, polimorfismos, adutos de DNA e proteínas, fatores epigenéticos e expressão gênica. Foi observado que testes de danos genéticos e epigenéticos são utilizados em frentistas de PRC que participam de programas de saúde do trabalhador ou de pesquisas, embora um baixo número de publicações sobre o tema tenha sido identificado. Esse fato talvez possa ser explicado pelos poucos países onde a profissão persiste e pelas limitações para o desenvolvimento de pesquisas nesses países. Conclusão: os bioindicadores de genotoxicidade e as técnicas de expressão gênica são úteis na detecção de dano precoce desta exposição ocupacional e devem ser avaliados em conjunto. Introduction: an exposure evaluation measures its intensity, frequencyand duration, detecting premature damage that, if ignored, might develop into a harmful framework. On environmental and occupational health fields, genotoxicity biomarkers have been widely used for this evaluation. Objective: to identify, describe and discuss main genotoxicity biomarkers and their use together with gene expression evaluation techniques in studies concerning occupational exposure to benzene in gas stations (GS). Methods: bibliographical review of studies published between 1995 and 2015. Results: the following techniques were identified: comet assay, oxidative stress, micronuclei, chromosomal aberrations, polymorphisms, DNA and protein adducts, epigenetic factors and gene expression. We observed that genetic and epigenetic damage tests are used in gas station attendants who participate in worker’s health programs or in researches, although a short number of publications on the theme have been identified. This can be explained by the small number of countries where such job still exists and by the limitations for developing research in such countries. Conclusion: genotoxicity biomarkers and gene expression techniques are useful for detecting the premature damage resulting from this occupational exposure and must be jointly evaluated.
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- 2017
145. Estratégias analíticas com cromatografia e espectrometria de massas para biomonitorização da exposição ao benzeno pela determinação do ácido S-fenilmercaptúrico urinário
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Leandro Vargas Barreto de Carvalho, Sérgio Rabello Alves, Leiliane Coelho André, Renato Marçullo Borges, Eline Simões Gonçalves, and Josino Costa Moreira
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chromatography and mass spectrometry ,Mass spectrometry ,chemistry.chemical_compound ,benzene ,Biomonitoring ,S-phenylmercapturic acid urinary ,Toxicologia ,benzeno ,Benzene ,Volume concentration ,trans-trans-muconic acid ,Chromatography ,lcsh:Public aspects of medicine ,lcsh:RA1-1270 ,Cromatografia gasosa ,General Medicine ,Environmental exposure ,Limiting ,chemistry ,ácido trans, trans-mucônico ,Environmental chemistry ,Espectrometria de massas ,cromatografia e espectrometria de massas ,ácido S-fenilmercaptúrico urinário ,Occupational exposure ,Exposição ocupacional - Abstract
Resumo Introdução: o benzeno é uma substância de reconhecida toxicidade e sua biomonitorização torna-se fundamental para a prevenção de danos à saúde humana, principalmente em situações de exposição ocupacional. Dentre os biomarcadores de exposição, o ácido S-fenilmercaptúrico é considerado o único específico, mas, devido a suas baixas concentrações na urina, é requerido o uso de técnicas analíticas sensíveis capazes de quantificar traços. Objetivo: revisar metodologias baseadas na cromatografia e na espectrometria de massas para a determinação do ácido S-fenilmercaptúrico. Método: revisão da literatura sobre a determinação do ácido S-fenilmercaptúrico urinário por técnicas de cromatografia e espectrometria de massas, nas principais bases de dados científicas, considerando o período entre 1951 e 2015. Resultados: 120 documentos serviram como base teórica para a construção desta revisão. A técnica analítica mais empregada foi o acoplamento da cromatografia a líquido com a espectrometria de massas. Contudo, os métodos diferem quanto ao preparo das amostras. Conclusão: o alto custo de aquisição e a manutenção de equipamentos são fatores limitantes para a difusão dos sistemas de cromatografia e espectrometria de massas. No entanto, sua elevada sensibilidade e seletividade faz com que essas técnicas, acopladas, possibilitem elucidar situações de exposição ocupacional e ambiental a poluentes, como o benzeno. Abstract Introduction: benzene is a substance of recognized toxicity and its biomonitoring of exposure becomes critical for preventing health damages, especially in occupational exposure situations. Among all the biomarkers of exposure, S-phenylmercapturic acid is considered the only specific one, but due to its low concentrations in urine, acute analytical techniques capable of quantifying traces must be used. Objective: to review methodologies based on chromatography and mass spectrometry for determination of S-phenylmercapturic acid. Method: literature review on the determination of urinary S-phenylmercapturic acid by chromatographic techniques and mass spectrometry in the main scientific databases, considering the period between 1951 and 2015. Results: 120 documents served as theoretical basis for the construction of this review. The analytical technique that was most applied was the coupling of liquid chromatography with mass spectrometry. However, the methods differ according to the preparation of samples. Conclusion: the high cost of equipment acquisition and maintenance are limiting factors for the diffusion of chromatography systems and mass spectrometry. Nevertheless, its high sensitivity and selectivity enable these coupled techniques to elucidate situations of occupational and environmental exposure to pollutants, such as benzene.
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- 2017
146. Identificação e Validação de Genes de Referência para a Normalização no Real-Time RT-qPCR em Arroz e Arroz Vermelho em Competição, sob Diferentes Doses de Nitrogênio
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Leandro Vargas, A.M. Nohato, Daiane de Pinho Benemann, Luis Antonio de Avila, and Dirceu Agostinetto
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0106 biological sciences ,0301 basic medicine ,Physiology ,QH301-705.5 ,Coefficient of variation ,Oryza sativa ,Plant Science ,Biology ,01 natural sciences ,Biochemistry ,03 medical and health sciences ,Transcription (biology) ,Reference genes ,Gene expression ,expressão gênica ,Biology (General) ,normalização ,Gene ,Genetics ,Red rice ,Botany ,Reverse transcription polymerase chain reaction ,030104 developmental biology ,normalization ,QK1-989 ,gene expression ,Agronomy and Crop Science ,010606 plant biology & botany - Abstract
Real time reverse transcription polymerase chain reaction (RT-qPCR) is an important technique to analyze differences in gene expression due to its sensitivity, accuracy, and specificity. However, before analyzing the expression of the target gene, it is necessary to identify and evaluate the stability of candidate reference genes for the proper normalization. This study aimed at evaluating the stability of candidate reference genes in order to identify the most appropriate genes for the normalization of the transcription in rice and red rice in competition under different nitrogen levels, as well as to demonstrate the effectiveness of the reference gene selected for the expression of the cytosolic ascorbate peroxidase (OsAPX2). Eleven candidate reference genes were assessed using the RefFinder which integrates the four leading software: geNorm, NormFinder, Bestkeeper, and the comparative delta-Ct method in addition to the analysis of variance to identify genes with lower standard deviation and coefficient of variation values. Eight out of the eleven genes have shown the desired effectiveness and, among them, the gene UBC-E2 has the highest stability according to RefFinder and the analysis of variance. The expression of the gene OsAPX2 has proven to be effective in validating the candidate reference gene. This study is the first survey on the stability of candidate reference genes in rice and red rice in competition, providing information to obtain more accurate results in RT-qPCR. RESUMO Reação em cadeia da polimerase da transcrição reversa em tempo real (RT qPCR) é uma técnica importante para analisar a expressão diferencial dos genes, devido à sua sensibilidade, exatidão e especificidade. No entanto, antes da análise da expressão do gene alvo, é necessário identificar e avaliar a estabilidade dos genes candidatos a referência para a normalização apropriada. O objetivo deste trabalho foi avaliar a estabilidade de genes candidatos a genes de referência, a fim de identificar os genes mais adequados para normalização da transcrição em arroz e arroz-vermelho em competição, sob diferentes doses de nitrogênio, e demonstrar a eficácia do gene de referência selecionado pela expressão da ascorbato peroxidase citosólica (OsAPX2). Onze genes candidatos a referência foram avaliados usando o aplicativo online RefFinder, que integra os quatro principais programas de software: geNorm, NormFinder, BestKeeper e método comparativo delta Ct, bem como fez-se análise de variância para identificar genes com menores valores de desvio-padrão e coeficiente de variação. Dos 11 genes, oito apresentaram eficiência dentro do padrão desejado, e, destes, o gene UBC-E2 foi o mais estável. A expressão do gene OsAPX2 mostrou-se eficiente para validação do gene candidato a referência. Este estudo é o primeiro levantamento sobre a estabilidade de genes de referência em arroz e arroz-vermelho em competição, fornecendo informações para obtenção de resultados mais precisos em RT-qPCR.
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- 2017
147. Avaliação do Mecanismo Responsável pela Resistência de Nível Baixo ao Glyphosate em Capim-Pé-de-Galinha
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André da Rosa Ulguim, Leandro Vargas, Jader Job Franco, Jessica Dias Gomes da Silva, and Dirceu Agostinetto
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0106 biological sciences ,absorption and translocation ,Physiology ,QH301-705.5 ,shikimate ,absorção e translocação ,Eleusine indica ,Chromosomal translocation ,Plant Science ,Plant anatomy ,01 natural sciences ,Biochemistry ,chemistry.chemical_compound ,cyt-P450 mono-oxigenase ,Biology (General) ,cyt-P450 monooxygenase ,EPSPs ,biology ,fungi ,Botany ,food and beverages ,04 agricultural and veterinary sciences ,Pesticide ,biology.organism_classification ,Horticulture ,chemistry ,Agronomy ,Glyphosate ,QK1-989 ,chiquimato ,040103 agronomy & agriculture ,0401 agriculture, forestry, and fisheries ,Malathion ,Phloem ,Weed ,Agronomy and Crop Science ,010606 plant biology & botany - Abstract
Goosegrass (Eleusine indica) infests various crops, being reported as low-level resistant (LLR) to glyphosate. The objectives of this study were to evaluate the mechanisms of resistance to glyphosate in goosegrass by the cyt-P450 complex to identify changes in leaf anatomy of these plants and quantify the accumulation of shikimate in biotypes susceptible and with LLR. The metabolic rate was assessed by applying the cyt-P450 malathion inhibitor 30 minutes before the herbicide application. The analysis of the leaf anatomy consisted of a characterization of anatomic cross-sections and evaluation of the effect of glyphosate on the leaf epidermis and the conducting vessels. Plant tissue was collected 24 hours after treatment (HAT) of the dose-response curve to evaluate the accumulation of shikimate. The LLR biotype has not shown glyphosate metabolism by the early application of malathion due to the control of about 65% with or without applying the inhibitor. There is no anatomical evidence to determine the differential absorption of glyphosate by LLR biotypes. However, there is evidence of lower absorption and translocation of glyphosate in this biotype by lower stomatal density and a smaller diameter of the phloem. However, the LLR biotype presents diameter of phloem of 0.027 mm and stomatal density of 91.23 mm-2, values which are below the observed ones on the susceptible biotype. The susceptible biotype presents shikimate accumulation 17% higher compared to the biotype with LLR at a dose of 1,080 g e.a. ha-1, allowing to infer that the resistance mechanism is related to the enzyme insensitivity to the herbicide, which enables the use of appropriate management practices to control this weed. RESUMO O capim-pé-de-galinha (Eleusine indica) é infestante de diversos cultivos, sendo relatado como resistente de nível baixo (RNB) ao herbicida glyphosate. Os objetivos deste trabalho foram avaliar mecanismos de resistência de capim-pé-de-galinha ao glyphosate, por meio de metabolização do herbicida pelo complexo cyt-P450, alterações na anatomia foliar e acúmulo de chiquimato nos biótipos suscetível e com RNB. A metabolização foi avaliada mediante a aplicação do inibidor de cyt-P450 malathion 30 min antes do herbicida. A análise da anatomia foliar constou da caracterização de cortes anatômicos e avaliação do efeito do glyphosate na epiderme foliar e nos vasos condutores. Para avaliar o acúmulo de chiquimato, foi coletado tecido vegetal 24 horas após tratamento (HAT) da curva de dose-resposta. O biótipo RNB não evidenciou metabolismo do glyphosate pela aplicação prévia de malathion, não diferindo do tratamento somente com o herbicida. Não existem evidências anatômicas que determinem a absorção diferencial do herbicida glyphosate pelo biótipo RNB. Entretanto, o biótipo RNB apresentou diâmetro do floema de 0,027 mm e densidade de estômatos de 91,23 mm-2, valores inferiores aos observados no biótipo suscetível, levando a indícios de menor absorção e translocação de glyphosate nesse biótipo. O biótipo suscetível apresentou acúmulo de chiquimato 17% superior, comparado ao biótipo RNB, na dose de 1.080 g a.e. ha-1, permitindo inferir que o mecanismo de resistência seja relacionado à insensibilidade da enzima-alvo ao herbicida, o que possibilita o uso de práticas de manejo adequadas para o controle dessa planta daninha.
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- 2017
148. Roteiro de inspeção sanitária de ambientes e processos de trabalho em postos de revenda de combustíveis: análise de usos e aplicações no estado de Santa Catarina
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Moura-Correa, Maria Juliana, Pinheiro, Regina Dal Castel, Carvalho, Leandro Vargas Barreto de, Menezes, Marco Antonio Carneiro, Nussbaumer, Luciana, Jacobina, Alexandre José Ribeiro, and Nobre, Letícia Coelho da Costa
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benzene ,avaliação de programas e instrumentos de pesquisa ,sanitary inspection ,occupational health ,posto de combustível ,gas station ,benzeno ,evaluation of research programs and tools ,inspeção sanitária ,saúde do trabalhador - Abstract
Resumo Introdução: o Roteiro de inspeção sanitária de ambientes e processos de trabalho em postos de revenda de combustíveis (RIAT-PRC) é utilizado para fins de vigilância em saúde pelo Centro de Referência em Saúde do Trabalhador (Cerest). Objetivo: descrever os usos e aplicações do RIAT-PRC a partir da experiência da vigilância em saúde do trabalhador do estado de Santa Catarina. Método: relato descritivo e analítico do instrumento RIAT-PRC e da avaliação de sua qualidade e uso no estado de Santa Catarina, no período de 2010 a 2014. Resultados: o roteiro foi aplicado em 459 PRC, com bom grau de preenchimento no geral. A aplicação do instrumento permitiu identificar baixa realização de monitoramentos biológicos e ambientais por parte das empresas. Também permitiu o acompanhamento das condições de trabalho e de saúde dos trabalhadores ao longo do tempo, bem como a possibilidade de identificar fatores e situações de risco nos ambientes de trabalho. Conclusão: o RIAT-PRC mostrou factibilidade para vigilância e para subsídio de estudos sobre exposição ao benzeno em PRC. Evidenciou-se a necessidade de aprimorar a capacitação das equipes técnicas para a efetiva vigilância da exposição ao benzeno e a outros agentes químicos presentes nos PRC. Abstract Introduction: the Form for Sanitary Inspection of Work Processes and Environments in Gas Stations (RIAT-PRC) is used for health surveillance by Reference Centers in Occupational Health (Cerest). Objective: to describe the uses and applications of the RIAT-PRC tool from the experience of the Surveillance of Occupational Health in the state of Santa Catarina, Brazil. Method: descriptive and analytical report of the RIAT-PRC tool and of the evaluation of its quality and use in Santa Catarina, from 2010 to 2014. Results: the form was introduced in 459 gas stations, with good filling degree in general. The application of the tool, made it possible to verify that the companies carried out only a few biological and environmental monitoring. It also allowed us to follow workers’ occupational and health conditions along the study time as well as to identify risk factors in work environments. Conclusion: the RIAT-PRC was useful for surveillance and for supporting studies on benzene exposure in gas stations. The results highlighted the need to improve the training of surveillance technical teams, aiming at an effective monitoring of gas stations workers’ exposure to benzene and other chemicals.
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- 2017
149. Classificação clínico-laboratorial para manejo clínico de trabalhadores expostos ao benzeno em postos de revenda de combustíveis
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Rita de Cássia Oliveira da Costa Mattos, Daniel Valente, Jorge Mesquita Huet Machado, Ariane Leites Larentis, Virgínia Dapper, Leandro Vargas Barreto de Carvalho, Paula de Novaes Sarcinelli, Isabele Campos Costa-Amaral, Marco Antônio Carneiro Menezes, Sérgio Rabello Alves, Maria Juliana Moura-Correa, Antônio Sérgio Almeida Fonseca, and Danilo Fernandes Costa
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manejo clínico ,benzene poisoning ,business.industry ,lcsh:Public aspects of medicine ,benzenismo ,worker’s health ,Medical practice ,lcsh:RA1-1270 ,General Medicine ,hemograma ,medicine.disease ,Health surveillance ,Broad spectrum ,hemogram ,Health care ,clinical management ,medicine ,Medical emergency ,business ,Clinical evaluation ,saúde do trabalhador - Abstract
Resumo Introdução: trabalhadores de postos de revenda de combustíveis estão expostos a compostos orgânicos voláteis, dos quais se destaca o benzeno. O manejo clínico do amplo espectro de sinais e sintomas desses trabalhadores ainda é um desafio para assistência em saúde. Objetivo: apresentar proposta de classificação clínico-laboratorial baseada na análise de hemograma e na avaliação clínica dos trabalhadores, para orientar a conduta dos profissionais de saúde. Métodos: a classificação clínico-laboratorial foi definida a partir de critérios de hierarquização dos resultados das avaliações clínicas e de vigilância à saúde de modo a possibilitar a organização dos procedimentos e fluxos de atenção à saúde. Resultados: a proposta define o manejo clínico com base na classificação dos expostos ao benzeno em quatro níveis de alterações clínico-laboratoriais que determinam os procedimentos compatíveis com o grau da exposição e de seus efeitos à saúde: 1) sem alterações significativas; 2) alterações inespecíficas ou incompletas, 3) alterações clínicas e/ou laboratoriais; 4) alterações sugestivas de benzenismo. Conclusão: a proposta de classificação dos achados clínico-laboratoriais é potencialmente capaz de orientar a conduta médica na avaliação das condições de saúde e dos riscos da exposição ao benzeno e de subsidiar o monitoramento sistemático e contínuo necessário para a definição de rotinas assistenciais para os coletivos de trabalhadores. Abstract Introduction: gas stations workers are exposed to volatile organic compounds, especially benzene. Clinical management of the broad spectrum of symptoms and signs observed in these workers is still a challenge for health care. Objective: to present a clinical-laboratory classification, based on hemogram analysis and clinical evaluation of workers exposed to benzene, as guidelines for health care professionals. Methods: the clinical-laboratory classification was defined based on priority-setting criteria for the results of clinical evaluations and health surveillance in order to allow the organization of health care flows and procedures. Results: the proposal defines the clinical management based on classification of workers exposed to benzene in four levels of clinical and laboratory alterations that determine procedures according to level of exposure and health effects: 1) without significant alterations; 2) unspecific or incomplete alterations; 3) clinical and/or laboratory alterations; and 4) alterations suggesting benzene poisoning. Conclusion: the proposal for classification of clinical and laboratory findings is potentially able to guide medical practice in the assessment of health conditions and risks of benzene exposure, and subsidize the systematic and continuous monitoring necessary for establishing health care practices offered to workers.
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- 2017
150. Influence of Vernalization and Photoperiod on the Duration of Stem Elongation and Spikelet Fertility in Wheat
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Leandro Vargas, Rafael Damo, Osmar Rodrigues, Mauro César Celaro Teixeira, and Edson Roberto Costenaro
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photoperiodism ,endocrine system ,media_common.quotation_subject ,Stem elongation ,food and beverages ,Fertility ,General Medicine ,Vernalization ,Biology ,eye diseases ,Horticulture ,Agronomy ,sense organs ,Cultivar ,Elongation ,reproductive and urinary physiology ,media_common - Abstract
A longer stem elongation phase (from the terminal spikelet-TS to the anthesis-ANT phases) increases grain production due to an increase in spikelet fertility. However, the mechanism behind the greater number of fertile flowers that occur when the duration of stem elongation is modified by photoperiod and vernalization is not fully understood. The goal of this study was to investigate the effect of combinations of photoperiod and vernalization on the duration of stem elongation and spikelet fertility in wheat. Thus, a greenhouse experiment was performed by subjecting 13 wheat genotypes to two vernalization regimes (V0—non-vernalized plants and V40—plants with 40 vernalization days) and to two photoperiod regimes (NP—natural and NP + 6—photoperiod extended by six hours), during the stem elongation phase. The natural photoperiod increased the spikelet fertility of eight cultivars without a corresponding increased duration of the TS-ANT phase, suggesting the existence of a direct effect of photoperiod on increased spikelet fertility. Vernalization increased the duration of the TS-ANT phase, without influencing spikelet fertility. There was genetic variability in the responses to photoperiod and vernalization.
- Published
- 2014
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