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Made available in DSpace on 2022-04-28T19:48:21Z (GMT). No. of bitstreams: 0 Previous issue date: 2022-03-01 Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) Changes in photosynthetic machinery can induce physiological and biochemical damage in plants. Low doses of glyphosate have been shown to exert a positive effect in mitigating the deleterious effects of water deficit in plants. Here, the physiological and biochemical mechanisms of safflower plants (Carthamus tinctorius L.) were studied under conditions of water deficit mediated by the attenuating effect of low-dose glyphosate. The plants were divided into two groups of water regimes in soil, without water deficit (−10 kPa) and with water deficit (−70 kPa), and were exposed to different concentrations of glyphosate (0, 1.8, 3.6, 7.2, 18, 36, 72, 180, 360, and 720 g a.e. ha−1). Evident protective responses at the physiological and biochemical levels were obtained after applying low doses of glyphosate to plants under water deficit, with a limiting dose for the occurrence of hormesis (LDS) = 72 g a.e. ha−1. The water deficit in plants resulted in hydrogen peroxide (H2O2) accumulation and consequently lipid peroxidation (LPO) associated with the accumulation of shikimic acid and glyphosate in plants, which triggered an increase in the activity of antioxidant enzymes such as superoxide dismutase (SOD), catalase (CAT), peroxidase (POD), and ascorbate peroxidase (APX) that act by dismuting the levels of reactive oxygen species (ROS), maintaining, and/or increasing the maximum quantum efficiency of photosystem II (Fv/Fm), effective quantum yield of photosystem II (ΦPSII), electron transport rate (ETR), photochemical extinction coefficient (qP), and non-photochemical extinction coefficient (NPQ). APX appears to be the main enzyme involved in eliminating H2O2. Low doses of glyphosate act as water deficit ameliorators, allowing the plant to maintain/increase metabolism at physiological and biochemical levels by activating antioxidant enzymes in the dismutation of ROS in safflower plants. São Paulo State University (UNESP) School of Agricultural Sciences Department of Crop Production Laboratory of Ecophysiology Applied to Agriculture (LECA) University of São Paulo (USP) College of Agriculture “Luiz de Queiroz” (ESALQ) Department of Exact Sciences São Paulo State University (UNESP) School of Agricultural Sciences Department of Crop Protection Center for Advanced Research on Weeds São Paulo State University (UNESP) School of Agricultural Sciences Department of Crop Production Laboratory of Ecophysiology Applied to Agriculture (LECA) São Paulo State University (UNESP) School of Agricultural Sciences Department of Crop Protection Center for Advanced Research on Weeds CNPq: 305952/2018-8 CNPq: 307208/2020-6

Made available in DSpace on 2021-06-25T10:16:36Z (GMT). No. of bitstreams: 0 Previous issue date: 2021-03-01 Plants exposed to suboptimal temperatures suffer damage to physiological processes, growth, development and yield. Acting as enhancers of physiological and metabolic performance of plants, biostimulants have been used to mitigate crop damage caused by abiotic stresses. This study aimed to determine which formulation and dosage of FH Attivus® biostimulant have the best effects on the development of bean plants exposed to suboptimal temperatures (

Made available in DSpace on 2021-06-25T10:16:23Z (GMT). No. of bitstreams: 0 Previous issue date: 2021-01-01 Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) To meet the growing demand for soybean it is necessary to increase crop yield, even in low water availability conditions. To circumvent the negative effects of water deficit, application of biostimulants with anti-stress effect has been adopted, including products based on fulvic acids and Ascophyllum nodosum (L.) seaweed extracts. In this study, we determined which formulation and dosage of a biostimulant is more efficient in promoting the recovery of soybean plants after stress due to water deficit. The experiment was conducted in a greenhouse, in a double-factorial randomized block design with two additional factors, four repetitions and eleven treatments consisting of three biostimulant formulations (F1, F2 and F3), and three dosages (0.25; 0.50 and 1.0 kg ha−1); a control with water deficit and a control without water deficit. Soybean plants were kept at 50% of the pot's water capacity for three days, then rehydrated and submitted to the application of treatments with biostimulant. After two days of recovery, growth, physiological, biochemical and yield parameters were evaluated. All plants that received the application of the biostimulant produced more than the water-stressed control plants. The biostimulant provided higher photosynthetic rates, more efficient mechanisms for dissipating excess energy and higher activities of antioxidant enzymes. Plants treated with biostimulant were more efficient in the recovery of the metabolic activities after rewatering, resulting in increased soybean tolerance to water deficit and reduced yield losses. The best result obtained was through the application of formulation 2 of the biostimulant at a dosage of 0.25 kg ha−1. Laboratory of Ecophysiology Applied to Agriculture School of Agricultural Sciences São Paulo State University (UNESP) Laboratory of Ecophysiology and Crop Production Federal Goianian Institute (IF Goiano), Campus Rio Verde Fertilizers Heringer Laboratory of Ecophysiology Applied to Agriculture School of Agricultural Sciences São Paulo State University (UNESP)

A pesquisa foi realizada com o objetivo de avaliar os componentes produtivos e variáveis fotossintéticas de plantas de milho cultivadas em quatro épocas de semeadura e quatro populações de plantas. O delineamento experimental foi em blocos casualizados, com parcelas subdivididas e quatro repetições. Nas parcelas foram alocadas as épocas de semeadura do milho safrinha (01 e 15 de fevereiro e 01 e 15 de março) e, nas subparcelas, as populações de plantas (50, 60, 70 e 80 mil plantas ha-1). As maiores taxas fotossintéticas e eficiência de carboxilação da Rubisco foram observadas nas plantas das semeaduras de 15/02 e 15/03. A semeadura realizada em 15/02 e 01/03 resultou na maior massa de 100 grãos e grãos por espiga. Em relação à produtividade de grãos, a única época que diferiu das demais foi a semeadura em 15/02, apresentando a menor média. As maiores médias de grãos por espiga e massa de 100 grãos foram observadas nas plantas da população de 50 mil plantas ha-1. As semeaduras realizadas em 15/02 e 15/03 favoreceram os processos fotossintéticos das plantas de milho. A maior produtividade ocorreu com a semeadura em 15/02. Menores populações de milho foram suficientes para garantir a satisfatória produtividade do milho safrinha.

Objetivou-se com esse trabalho avaliar a infestação de plantas daninhas após cinco anos de cultivo com milho solteiro ou consorciado com Brachiaria ruziziensis no outono-inverno. Os tratamentos foram estabelecidos em áreas com diferentes períodos de consórcio (milho+braquiária) e cultivos do milho solteiro entre 2011 a 2015, sendo milho solteiro de 2011 a 2015, consórcio em 2011 + milho solteiro de 2012 a 2015, consórcio em 2011 e 2012 + milho solteiro de 2013 a 2015, consórcio de 2011 a 2013 + milho solteiro em 2014 e 2015, consórcio de 2011 a 2014 + milho solteiro em 2015, consórcio de 2011 a 2015, milho solteiro em 2011 + consórcio de 2012 a 2015, milho solteiro em 2011 e 2012 + consórcio de 2013 a 2015, milho solteiro de 2011 a 2013 + consórcio em 2014 e 2015, milho solteiro de 2011 a 2014 + consórcio em 2015. As maiores massas secas de Coniza spp. foram observadas nos tratamentos milho solteiro 2011 a 2015, consórcio 2011 e 2012 + milho solteiro 2013 a 2015 e consórcio 2011 a 2013 + milho solteiro 2014 e 2015 e de Digitaria spp. nos tratamentos milho solteiro 2011 a 2015, consórcio 2011 + milho solteiro 2012 a 2015 e consórcio 2011 e 2012 + milho solteiro 2013 a 2015. No ano de cultivo, o consórcio milho-braquiária aumenta a massa total de resíduos e inibe a presença de plantas daninhas. A reinfestação por Coniza spp. ocorre após um ano sem consórcio e de Digitaria spp. após dois anos sem consórcio, porém em menores quantidades do que na sucessão soja-milho safrinha.

This study aims to discover the agro-economic yield of the ‘Comum’ tannia, which was propagated with five seedling types (Extra, Large, Medium, Small and Tiny) and grown both with and without a hilling operation during three crop seasons. In each agricultural year, the treatments were arranged as a 5 x 2 factorial in a randomized complete block design with four replications. The harvests were conducted 238 (2007-08), 231 (2008-09) and 237 (2009-10) days after planting. The data were submitted to an analysis of variance each year. The plants produced from large seedlings and RM-corms had a higher fresh leaf weight. Additionally, the dry weight of the RFC-commercial cormels and RFNC-non-commercial cormels was higher with extra seedlings. The plants grown during 2008-2009 had a higher fresh weight of RM and of RFNC than the plants grown during 2009-10. The interaction between the seedling types and crop seasons significantly influence the yield and dry weight of the leaves of RM and RFC, the leaf length of RM and RFC and the leaf diameter of RFC. According to the economic analysis, a net income of R$ 2,234.08 was obtained when the tannia were cultivated without a hilling operation using extra propagated seedlings.

Made available in DSpace on 2018-12-11T00:10:50Z (GMT). No. of bitstreams: 1 ID36732.pdf: 375146 bytes, checksum: ef5a07fe2f2541974cc00174047bf0db (MD5) Previous issue date: 2018-12-10

Made available in DSpace on 2018-12-07T23:47:47Z (GMT). No. of bitstreams: 1 ID36727.pdf: 178004 bytes, checksum: dbd2b7f2383b4f60e10efc0fa468d084 (MD5) Previous issue date: 2018-12-07