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Belonging to the Brazilian flora, the species Hancornia speciosa (Gomes), known as mangabeira, has bioactive compounds of interest, such as flavonoids, xanthones, and proanthocyanidins. The objective of this study was to determine how the supplementation of sugars in culture medium affects the osmotic potential of the medium, as well as its influence on cell growth and on the concentration of phenolic compounds. For this purpose, after 90 days of subculture, 20 mL aliquots of the cultures were added to flasks containing 20 mL of medium with different sugars (glucose, fructose, sucrose, mannitol, and sorbitol) under a 16-h photoperiod with a spectral range between 400 and 700 nm of photosynthetically active radiation (45–55 μmol m−2 s−1) in a shaker at 110 rpm. After 30 days, the pH, electrical conductivity, osmotic potential, biomass accumulation, and concentrations of phenolic compounds were evaluated. Regardless of their concentration in the medium, the sugars sorbitol and mannitol provided more unfavorable conditions for water absorption at the cellular level, reducing the water potential of the medium. Sucrose favored greater water absorption and biomass accumulation. Among the various sugar concentrations, 3% (30 g/L) sucrose or glucose improved the accumulation of fresh and dry cell weight and the production of polyphenols such as chlorogenic acid, epicatechin, rosmarinic acid, hesperidin, rutin, and quercetin. In addition, they resulted in a higher osmotic potential of the medium and larger cells than other carbon sources. Despite the differences in cell size, no culture conditions compromised cell survival.

Chitosan induces plant tolerance to various abiotic stresses, including water deficit. However, its use may be limited, due to its constitution and low solubility in water. Thus, chemical modifications were proposed in this study with the objective of potentializing its biological effects in maize plants. The derivatives were semi-synthesized (N-succinyl and N,O-dicarboxymethyl) and, together with chitosan, they were applied, via the leaf, in a drought-sensitive maize hybrid (BRS1030) under pre-flowering water deficit. The water deficit was maintained for 15 days and the analyses were performed at the beginning and end of stress, and also in rehydration. Leaf water potential, gas exchange, chlorophyll fluorescence, and content of chloroplastidic pigments were evaluated. The use of the derivatives modulated photosynthesis parameters, affecting the involved mechanisms, such as stomatal activity, water use efficiency and photosystem II activity. Chlorophyll fluorescence indicated that the antenna complex was damaged by the water deficit condition, with a decrease in the energy flux in the electron transport chain and in the photochemical phase of photosynthesis. However, the spraying of chitosan derivatives induced tolerance to water deficit, suggesting that chitosan derivatives are more bioavailable to plants. Water stress decreases pigment content, but both the application of chitosan and derivatives increased these contents. It is concluded that chitosan derivatives improved the photosynthetic parameters in maize susceptible to drought, inducing tolerance to this stress, and the possible reasons and consequences are discussed. Made available in DSpace on 2019-08-30T00:56:20Z (GMT). No. of bitstreams: 1 ActionNsuccinyl.pdf: 2563228 bytes, checksum: 0be3a70547206a76b4f08e780fd58f27 (MD5) Previous issue date: 2019

Water deficit severely compromises the homeostatic balance of plants and suggests a redox imbalance in cells. Melatonin is described as a promoter of stress tolerance in plants that induces the expression of stress-related genes, reduces lipid peroxidation and increases the antioxidant system. To analyze the influence of exogenous melatonin on the promotion of tolerance to water deficit, we applied concentrations of 300 μM and 500 μM to Coffea arabica L. seedlings. Here, we show that the intensity of the short-term responses to melatonin may vary according to the concentration of melatonin. We also report that lower concentrations of melatonin (300 μM) promote an increase in the root system and the protection of the photosynthetic apparatus, allowing greater gas exchange, greater carboxylation efficiency and higher chlorophyll contents. Moreover, melatonin improved the activity of the enzymatic and nonenzymatic antioxidant systems and reduced lipid peroxidation. In addition, we demonstrated that higher concentrations (500 μM) caused negative effects on stress tolerance, thus demonstrating a toxic level. Overall, these results demonstrated that melatonin mediates the signaling for water deficit responses by acting as an inductor of tolerance, most likely enhanced by increased carboxylation efficiency and antioxidant systems. This study provides evidence that exogenous melatonin protects coffee against water deficit.

This study was conducted to assess the effects of silicon treatments on architecture and morphometry of root systems of sorghum plants grown at two different soil water levels and to elucidate whether physiological improvements caused by silicon were related to morphometric modifications of the root system. Methods Plants of the sorghum genotype BRS332 which is sensitive to drought at pre-flowering stage were used in this study. Theseplantsweregrowninagreenhouse,eitheratfieldcapacityorunderwaterdeficiency,andweretreatedwithsiliconorwere untreated. Leaf water potential was evaluated at noon, and gas exchange, photosynthetic pigment levels, relative aquaporin expression, root system morphometry, and grain yield were assessed. Results Silicontreatmentsmitigatedtheeffectsofwaterdeficiencyonleafpotential,photosynthesis,instantaneouscarboxylation efficiency, and morphometry of the root system. These positive effects contributed to a higher grain yield, and thus indicated highertolerancetodrought.Thebeneficialeffectsofsiliconalsooccurredinplantsgrownatfieldcapacity.Silicontreatmentsdid not increase the relative expression of aquaporin genes. However, we observed that expression of aquaporin TIP4 responded more strongly to drought than that of aquaporins PIP1;6 and PIP1;3/1;4. Conclusion Weconcludethatsiliconsupplementationincreasesthetoleranceofsorghumplantstodroughtbyincreasinggrowth of the root system and mitigating adverse effects of drought on photosynthesis. Made available in DSpace on 2020-11-13T20:54:44Z (GMT). No. of bitstreams: 1 Silicon-supplementation.pdf: 735343 bytes, checksum: 5fa0629f10561528687c5e6d5e56776c (MD5) Previous issue date: 2020 Publicado online em 12 dez. 2019.

Ocimum gratissimum L. is appreciated for its condiment and medicinal properties. Its essential oil has antifungal and antioxidant activity, being valuable for pharmaceutical and commercial applications. However, plants usually do not produce a large amount of essential oil. In this sense, studies have been conducted to shown that it is possible to increase essential oil synthesis through elicitation. Therefore, the aim of this work was to use the elicitor Salicylic acid (SA) on O. gratissimum to enhance its essential oil production. Plants were subjected to elicitation treatment with SA solutions of 0, 0.5, 1.0 and 1.5 mM. Fresh leaves were used for essential oil extraction after 10 days of elicitation, and antioxidant system analysis was performed throughout this period. Elicitation with SA promoted an increase in the percentage content of O. gratissimum essential oil by 39.8% compared to control plants. An increase of 4.2% in eugenol, its major compound, was also observed. Additionally, changes in signaling defense response were detected in elicited plants. There was an increase in enzymes activity, Superoxide Dismutase and Catalase, and also the content of hydrogen peroxide and lipid peroxidation were higher in elicited plants. Therefore, the elicitation with SA influenced O. gratissimum antioxidant system and its essential oil production.

Silicon (Si) supplementation is related to the induction of different tolerance mechanisms, leading to higher farm crop yields. The objective of this study was to elucidate the Si action mechanisms as a beneficial element in primary, antioxidant, and osmoregulatory metabolism in sorghum plants cultivated in soil under two different water availability conditions. Plants of the sorghum BRS332 genotype, sensitive to drought, were cultivated in pots in greenhouse conditions until harvest. At the pre-flowering stage, the following treatments were applied: field capacity (irrigated plants), water deficit, field capacity with Si application, and water deficit with Si application. Water deficit was conducted over 12 days, after which water potential and photosynthetic rate analyses, and leaf and root harvesting for biochemical analyses were performed. After the water deficit treatment, all plants were returned to normal irrigation until harvest, when the yield components were analyzed. Si supply occurred via fertilization at a concentration of 2 mM applied to the soil in a volume of 250 mL per day over 17 days, which corresponded to a supply on the five days preceding the beginning of stress, plus a 12-day supply during the stress period. Si alleviated the water deficit in plants, resulting in higher water potential, photosynthetic rate, grain biomass, and harvest index. Si increased the antioxidant enzymatic activity, and increased non-enzymatic antioxidants such as ascorbate and osmoregulatory substances, including proline, soluble and reducing sugars, and sucrose. Plants treated with Si showed lower damage to cell membranes (lower lipid peroxidation). The beneficial effects of Si also extended to plants that were not subjected to the water deficit treatment. Si uses the peroxide pathway as a signal to regulate metabolic responses.

Práticas alternativas de manejo são necessárias para minimizar a necessidade por fertilizantes minerais em sistemas de cultivos com culturas não leguminosas. Os níveis de adubação empregados, em especial com os macronutrientes primários NPK, geralmente influenciam a taxa de crescimento e o desenvolvimento do milho, com reflexos positivos na produção da cultura. Neste estudo, objetivou-se avaliar o efeito de doses de adubação e fontes de formulados mineral e organomineral no crescimento, desenvolvimento e leitura de SPAD de plantas de milho. O experimento foi realizado em vasos plásticos, dispostos a céu aberto, preenchidos com 25 L de solo, coletado da camada de 0 a 0,20 m, de um Latossolo Vermelho distrófico de Cerrado, na Fazenda Experimental do Instituto Federal Goiano, Campus Rio Verde - GO. O delineamento experimental utilizado foi de blocos ao acaso em esquema fatorial 5x2, com quatro repetições, constituídos por cinco doses de formulado NPK 04-14-08 (0, 150, 300, 450, 600 kg ha-1 do produto, equivalente para vaso) e duas fontes de fertilizantes mineral e organomineral da formulação, 04-14-08. Nas plantas, foram realizadas avaliações das características agronômicas, a cada quinze dias (30, 45, 65, 75 dias após emergência), de altura de planta, diâmetro do colmo, número de folhas, leitura SPAD e área foliar. A dose de 600 kg ha-1 do formulado 04-14-08 proporciona o melhor desenvolvimento de diâmetro do colmo e altura de planta. A fonte organomineral proporciona maior altura de planta de milho, número de folhas e área foliar. O fertilizante organomineral apresenta eficiência para garantir o crescimento e desenvolvimento do milho.

O conhecimento da extração e acúmulo de nutrientes pelas plantas durante seu desenvolvimento auxilia na determinação das suas necessidades nutricionais e é relevante para aprimorar a recomendação de fertilizantes minerais e organominerais. Objetivou-se avaliar o efeito de doses de fontes de formulado NPK mineral e organomineral na produtividade de massa seca da parte aérea e no acúmulo de macronutrientes e micronutrientes pelo milho. O experimento foi realizado em vasos plásticos, dispostos a céu aberto, preenchidos com 25 L de solo, coletado de um Latossolo Vermelho distrófico, fase cerrado, na Fazenda Experimental do Instituto Federal Goiano, Campus Rio Verde - GO. O delineamento experimental utilizado foi de blocos ao acaso, em esquema fatorial 5x2, com quatro repetições. Os tratamentos foram cinco doses de formulado NPK 04-14-08 (0, 150, 300, 450, 600 kg ha-1do produto, equivalente para vaso) e duas fontes de fertilizantes: mineral e organomineral da formulação, 04-14-08. A colheita das plantas de milho foi realizada aos 75 dias após a semeadura, com corte do colmo rente ao solo. Nas plantas, foram realizadas avaliações de produtividade de massa seca da parte aérea e acúmulo de macronutrientes (N, P, K, Ca, Mg e S) e micronutrientes (Cu, Fe, Mn e Zn). A fonte organomineral proporcionou maior produtividade de matéria seca ao milho. O acúmulo de nutrientes seguiu a ordem decrescente N > K > Mg > Ca > S > P > Fe > Mn > Zn > Cu. A fonte organomineral, nas mesmas doses do formulado mineral, apresenta potencial de substituir as fontes minerais.

The present study combined evaluations of agronomic parameters such as roots morphometry (using the WinRhizo program) and leaf gas exchange, in order to detect features in the root system which allow the maintenance of photosynthetic rates and productivity in four maize genotypes contrasting for tolerance to water deficit (WD), two tolerant (DKB 390 and BRS1055) and two sensitive (BRS 1010 and 2B710). The genotypes showed similar tolerance to dehydration of leaf tissue, but the tolerant genotypes DKB 390 and BRS1055 presented higher photosynthetic rate and yield compared to the sensitive BRS 1010 and 2B710. Nevertheless, divergent strategies of adaptation to drought among tolerant genotypes were observed. The genotype DKB 390 presented physiological mechanisms in shoots responsible for minimizing water loss, which decreases the dependence of root adjustments to increase the absorption of water. In turn, the BRS 1055 genotype showed a drought avoidance strategy by producing fine roots associated with a higher leaf area.

– This study associated data of performance, gas exchange and morphometric analysis of the root system using the WinRhizo software. The main objective was to verify how the modifications in the root system contribute to maintain the photosynthetic rates and productivity in sorghum hybrids divergent regarding tolerance to water deficit. The 1G 282 tolerant hybrid presented higher tolerance to desiccation of the leaves, higher grain productivity (68.33%) and maintained its photosynthetic rate 2.13 times higher compared to the sensitive BRS 332 during the water deficit. Both hybrids presented responses related to desiccation prevention, characterized by modifications of the root system that are capable to benefit absorption of water and nutrients under stress. Besides, 1G 282 showed more developed and responsive root system, especially due to a higher superficial area of very fine roots (42.67%), volume of fine roots (36.90%) and very fine roots (53.18%) under water deficit when compared to the sensitive BRS 332 at the same conditions. Keywords: Sorghum bicolor , roots, WinRhizo, photosynthesis. MODIFICACOES DO SISTEMA RADICULAR, TROCAS GASOSAS E PRODUTIVIDADE EM HIBRIDOS DE SORGO CULTIVADOS SOB DEFICIT HIDRICO RESUMO – O estudo em questao associou dados de rendimento, trocas gasosas e morfometria do sistema radicular utilizando o software WinRhizo. O principal objetivo foi verificar como modificacoes do sistema radicular contribuem para a manutencao da taxa fotossintetica e produtividade em hibridos de sorgo divergentes para tolerância ao deficit hidrico (WD), sendo um tolerante (1G 282) e outro sensivel (BRS 332). O hibrido tolerante 1G 282 apresentou maior tolerância a desidratacao do tecido foliar, alem de manter uma taxa fotossintetica 2,13 vezes maior e maior rendimento de graos (68,33%) em relacao ao sensivel BRS 332 durante o WD. Ambos os hibridos apresentaram respostas de prevencao a seca, caracterizada por modificacoes do sistema radicular capazes de favorecer a absorcao de agua na condicao de estresse. No entanto,1G 282 demonstrou possuir um sistema radicular mais desenvolvido e responsivo, especialmente por exibir maior area superficial de raizes muito finas (42,67%) e volume de raizes finas (36,90%) e muito finas (53,18%) em condicao de WD, quando comparado com o sensivel BRS 332 nas mesmas condicoes de cultivo. Palavras-chave: Sorghum bicolor , raizes, WinRhizo, fotossintese.

As Droseraceaeas são uma família de plantas carnívoras, características de solos pobres em nutrientes, úmidos e depauperados, com adaptações que capturam presas, absorvem seus metabólitos e os utilizam em seu crescimento e desenvolvimento. As folhas são revestidas, na face adaxial, por estruturas que produzem uma substância mucilaginosa, composta por enzimas proteolíticas, utilizada para aprisionar e digerir eventuais vítimas. Estas plantas possuem ampla distribuição geográfica, estando representados em quase todas as regiões do mundo. No Brasil são frequentemente encontradas em floriculturas ou feiras apesar de serem exigentes em relação ao substrato. A disponibilidade de nutrientes é considerada, de forma geral, o principal fator abiótico que limita a propagação de plantas carnívoras. A carência de trabalhos científicos sobre as espécies de plantas carnívoras, associada à dificuldade de adequar o substrato ideal para o seu desenvolvimento e crescimento, são os principais motivos para a realização do presente trabalho. Assim sendo, objetivou-se avaliar as características de crescimento e desenvolvimento, bem como as estruturas morfoanatômicas da espécie Drosera spathulata cultivadas em diferentes substratos. Como resultado, a fibra de coco proporcionou melhor pegamento das plantas, enquanto maior número de folhas foi obtido utilizando-se a Fibra de coco e a mistura entre Fibra de coco (80%) e Turfa (20%). As características morfoanatômicas foram parâmetros importantes na classificação da espécie Drosera spathulata.

We test if maize maintain yield under long-term drought throught improvement of photosyntheis (A) coupled with up-regulation of the antioxidant system induced by increase in levels of abscisic acid (ABA). Four maize genotypes with constrasting drought tolerance: BRS1010 and 2B710 (sensitive) and DKB 390 and BRS1055 (tolerant) in two soil water levels, field capacity (FC) and water deficit (WD) were used. WD was applied at the pre-flowering stage for 12 days, and oxidative damage was measured as malondialdehyde (MDA) accumulation in whole plant. Plants from tolerant genotypes DKB390 and BRS1055 showed higher A and had no signal of oxidative damage compared to sensitive genotypes 2B710 and BRS1010 under WD, resulting in a higher yield attributes. For our surprising, it was dissociated from up-regulation of the antioxidant system ABA-mediated. In turn, plants from two sensitive genotypes under WD showed compared to FC consistent reduction of A due to mesophyll conductance (gm) limitation. Only WD plants from sensitive genotype BRS1010 presented leaf ABA levels increased related to its counterparts under FC; however, due to the inactivation of catalase activity the oxidative damage control was not effective, resulting a hardly MDA acumulation in both leaves and roots. The maize tolerance under long-term drought is linked to scape of gm decline.

Os residuos originados do processamento de frutas contem muitos nutrientes. Considerando os altos indices de desperdicio de alimentos e o consideravel valor nutricional, merece destaque a secagem de residuos para obtencao de farinha como ingrediente alimentar rico em fibras para incorporacao nos mais diversos alimentos em substituicao parcial a farinha de trigo, portanto o pr esente trabalho teve por objetivo avaliar a aplicacao tecnologica da farinha de residuo do processamento da acerola ( Malpighia emarginata D.C.) na confeccao de biscoitos tipo lingua de gato. Estes foram elaborados substituindo-se 20% da farinha de trigo e avaliados quanto as caracteristicas centesimais : u midade , residuo mineral ou fracao de cinzas , proteina bruta , extrato etereo , fibra bruta , carboidratos e valor calorico , alem das analises microbiologicas (coliformes, Staphylococcus sp. e Salmonella sp. ) . O teste de aceitabilidade foi realizado atraves de escala hedonica 9 pontos. Os biscoitos adicionados de farinha de residuo de acerola apresentaram boas quantidades de lipideos, proteinas, materia mineral e carboidratos, e, quando comparados aos biscoitos confeccionados sem o residuo, apresentaram maiores teores de fibras e menor valor calorico. A aceitabilidade foi muito boa, apresentando medias sensoriais positivas para os atributos sabor, textura e aroma. De maneira geral, observou-se que a insercao de farinhas de residuos ricas em fibras alimentares, pode melhorar a qualidade nutricional dos biscoitos sem comprometer suas caracteristicas sensoriais, alem de apresentar-se menos caloricos e oferecer uma alternativa para o aproveitamento do residuo de maneira economica e nutritiva.

O objetivo do presente trabalho foi verificar o efeito da aplicacao dos inseticidas thiamitoxan e imidaclopride, em diferentes doses, sobre os parâmetros de desenvolvimento das mudas de cafeeiro. O experimento foi instalado em viveiro comercial em Muzambinho-MG, no periodo de julho de 2010 a fevereiro de 2011. As mudas foram formadas em saquinhos de polietileno perfurados, que apos encanteirados, procedeu-se a semeadura com duas sementes de Coffea arabica L., cultivar Catuai Vermelho IAC 144. Os tratamentos constituiram-se: T1: 2 aplicacoes de imidaclopride(1ml.L -1 agua) nos estagios orelha de onca e 2° par de folhas verdadeiras;T2: 1 aplicacao de imidaclopride (1ml.L -1 agua) no estagio de orelha de onca; T3: 2 aplicacoes de thiamitoxan(0,5g.L -1 agua) nos estagios orelha de onca e 2° par de folhas verdadeiras; T4: 1 aplicacao de thiamitoxan(0,5g.L -1 agua) no estagio de orelha de onca; T5: Testemunha. O delineamento experimental utilizado foi o de Blocos Casualizados, sendo quatro o numero de repeticoes por tratamento. Aos 180 dias apos a instalacao do experimento, as oito mudas centrais da parcela util foram retiradas e avaliadas nas caracteristicas: altura, diâmetro do caule, numero de pares de folhas, biomassa fresca e seca da parte aerea e raiz. Os tratamentos com o inseticida thiametoxan (2 aplicacoes) proporciona melhor desenvolvimento das mudas de cafeeiros com efeito positico sobre o diâmetro de caule e biomassa fresca e seca do sistema radicular. Por outro lado, a aplicacao de imidaclopride prejudica o desenvolvimento das mudas de cafeeiros.

The objective of this study was to evaluate the physiological quality of sorghum seeds under water stress. For the experiment, five lots of sorghum seeds with the same genotype (CMX5156A) and different physiological qualities were used. Five lots were submitted to different combinations of hypoxia time (4, 8, 16, 24, 36, and 48 hours under water) and temperature (20, 30, and 40°C). The moisture content, percentage of germination and emergence, height, and dry matter of seedlings from soaked seeds, were determined. A completely randomized experimental design in a 5 x 6 x 3 factorial, with four replicates, was used. The effect of hypoxia stressed the sorghum seed, affecting the germination of the seeds and emergence, dry mass, and height of the seedlings. The greatest decreases in viability and vigor were observed at higher temperatures and flood times. It is concluded that the germination and vigor of sorghum seeds are adversely affected by flooding. The submersion of seed in water at 40°C for 24 hours allows the segregation of sorghum seed lots. Made available in DSpace on 2021-12-28T18:00:23Z (GMT). No. of bitstreams: 1 germination-vigor.pdf: 368060 bytes, checksum: 511988a5487b808ee147385ad282d853 (MD5) Previous issue date: 2021

– Drought is considered the primary limitation to agriculture and, can reduce grain yield by up to 60% when occurs at pre-flowering in maize. In this context this research, aimed to understand the maize genotypes behavior to drought management and carbon partitioning between grain production and structures to maintain hydration when submitted to drought. Maize genotypes tolerant (DKB390 and P30F35) and sensitive (BRS1010 and 2B710) to drought were grown in a greenhouse using two water conditions: irrigated and stressed. Water deficit was imposed at pre-flowering and maintained for twelve days. Leaf water potential, gaseous exchange and male and female flowering interval were evaluated. At the end of the cycle, production components and root/shoot ratio dry weight were evaluated. Drought-tolerant genotypes used root system as a mechanism of tolerance to drought, which ensure greater efficiency in absorption and loss of water and, consequently, greater stomatal conductance during the drought, compared to the sensitive-genotypes. In addition, drought-tolerant genotypes showed greater stability in the source-sink relationship, exhibiting higher photosynthetic rate and harvest index.Keywords: water stress, carbon partitioning; root/shoot ratio dry weight, gas exchanges, Zea mays.GENÓTIPOS DE MILHO TOLERANTES À SECA INVESTEM EM SISTEMA RADICULARE MANTEM ALTO ÍNDICE DE COLHEITA DURANTE O ESTRESSE HÍDRICORESUMO- A seca é considerada restrição primária à agricultura, e no milho, quando ocorre no pré-florescimento, pode reduzir o rendimento de grãos em até 60%. Neste contexto, objetivou-se entender como genótipos de milho contrastantes para tolerância à seca, gerenciam o particionamento de carbono entre produção de grãos e estruturas de manutenção da hidratação durante a seca. Para isso, em casa de vegetação cultivaram-se genótipos de milho tolerantes (DKB390 e P30F35) e sensíveis (BRS1010 e 2B710) à seca, em duas condições hídricas: irrigado normal e déficit hídrico. No pré-florecimento foi imposto o déficit hídrico, que foi mantido por doze dias. Posteriormente avaliou-se o potencial hídrico foliar, trocas gasosas e intervalo de florescimento masculino e feminino. No final do ciclo, avaliaram-se os componentes de produção e a razão raiz/parte aérea. Constatou-se que, genótipos tolerantes utilizaram preferencialmente sistema radicular como um mecanismo de tolerância à seca, o que garantiu a esses genótipos, maior eficiência entre a absorção e perda de água e, consequentemente, maior condutância estomática durante a seca, em relação aos genótipos sensíveis. Além disso, os genótipos tolerantes apresentaram maior equilíbrio em suas relações fonte e dreno, exibindo maiores taxa fotossintética e índice de colheita.Palavras-chave: estresse hídrico, particionamento de carbono, razão raiz/parte aérea, trocas gasosas, Zea mays.