Alterações morfo-anatômicas e bioquímicas de genótipos de feijão-caupi submetidos ao déficit hídrico
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Data
2022-02-11
Autores
Melo, Andressa Aparecida Rodrigues de
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Universidade Estadual Paulista (Unesp)
Resumo
A seca é um dos maiores estresse abiótico que interfere na produção agrícola do mundo. O feijão-caupi é uma importante fonte de proteína na alimentação humana e animal, sendo cultivados em regiões áridas e semi-áridas no mundo. O objetivo do experimento I: Foi avaliar o efeito de diferentes níveis de capacidade de água no solo (CAD) (20, 40, 60, e 80% da CAD) na fixação biológica do nitrogênio, ajuste osmótico celular e produtividade do feijão-caupi. Os resultados desse estudo sugerem que a redução do número de nódulos e acúmulo de ureídeos foram as principais respostas fisiológicas para a redução do crescimento e produtividade causados pela umidade do solo abaixo de 40%. O objetivo do experimento II: Foi avaliar a resposta morfofisiológica, bioquímica e anatômicas de raízes, folhas e nódulos de genótipos de feijão caupi, sensíveis: BRS Tracuateua (G1) e BRS Tumucumaque (G2), e tolerantes: Pingo de ouro 1-2 (G3) e BRS Marataoã (G4) submetidos ao déficit hídrico (CAD 40%) ou não (CAD 80%). As variáveis que possibilitou o agrupamento entre os genótipos tolerantes foram condutância estomática, fotossíntese e o acúmulo de sacarose, glicose, sorbitol e frutose nas raízes. Anatomicamente, o genótipo G4 apresentou melhor desenvolvimento do nódulo, células do córtex bem desenvolvidas e feixes vasculares mais organizados. Maior quantidade de grãos de amido foram encontrados nas folhas dos genótipos da CAD 40%, sendo maior no genótipo G4 em decorrência do aumento do floema nas raízes. A microscopia eletrônica de transmissão revelou que o genótipo G4 apresentou organização de grana. Nas raízes foi possível observar que os elementos de vasos do genótipo G2 apresentaram maior diâmetro na CAD 40%, comportamento que não ocorreu no genótipo G4.
Drought is one of the biggest abiotic stresses that interfere with agricultural production in the world. Cowpea is an important source of protein in human and animal food, being cultivated in arid and semi-arid regions in the world. The objective of experiment I: It was to evaluate the effect of different levels of soil water retention capacity (SWRC) (20, 40, 60, and 80% of SWRC) on biological nitrogen fixation, cellular osmotic adjustment and productivity of cowpea. The results of this study suggest that the reduction in the number of nodules and accumulation of ureides were the main physiological responses to the reduction in growth and productivity caused by soil moisture below 40%. The objective of experiment II: It was to evaluate the morphophysiological, biochemical and anatomical response of roots, leaves and nodules of cowpea genotypes, sensitive: BRS Tracuateua (G1) and BRS Tumucumaque (G2), and tolerant: Pingo de ouro 1-2 (G3) and BRS Marataoã (G4) submitted to water deficit (SWRC 40%) or not (SWRC 80%). The variables that allowed the grouping between the tolerant genotypes were stomatal conductance, photosynthesis and the accumulation of sucrose, glucose, sorbitol and fructose in the roots. Anatomically, the G4 genotype showed better nodule development, welldeveloped cortex cells and more organized vascular bundles. Greater amount of starch grains were found in the leaves of the 40% CAD genotypes, being higher in the G4 genotype due to the increase in phloem in the roots. Transmission electron microscopy revealed that the G4 genotype showed granum organization. In the roots, it was possible to observe that the vessel elements of the G2 genotype presented greater diameter in the 40% CAD, a behavior that did not occur in the G4 genotype.
Drought is one of the biggest abiotic stresses that interfere with agricultural production in the world. Cowpea is an important source of protein in human and animal food, being cultivated in arid and semi-arid regions in the world. The objective of experiment I: It was to evaluate the effect of different levels of soil water retention capacity (SWRC) (20, 40, 60, and 80% of SWRC) on biological nitrogen fixation, cellular osmotic adjustment and productivity of cowpea. The results of this study suggest that the reduction in the number of nodules and accumulation of ureides were the main physiological responses to the reduction in growth and productivity caused by soil moisture below 40%. The objective of experiment II: It was to evaluate the morphophysiological, biochemical and anatomical response of roots, leaves and nodules of cowpea genotypes, sensitive: BRS Tracuateua (G1) and BRS Tumucumaque (G2), and tolerant: Pingo de ouro 1-2 (G3) and BRS Marataoã (G4) submitted to water deficit (SWRC 40%) or not (SWRC 80%). The variables that allowed the grouping between the tolerant genotypes were stomatal conductance, photosynthesis and the accumulation of sucrose, glucose, sorbitol and fructose in the roots. Anatomically, the G4 genotype showed better nodule development, welldeveloped cortex cells and more organized vascular bundles. Greater amount of starch grains were found in the leaves of the 40% CAD genotypes, being higher in the G4 genotype due to the increase in phloem in the roots. Transmission electron microscopy revealed that the G4 genotype showed granum organization. In the roots, it was possible to observe that the vessel elements of the G2 genotype presented greater diameter in the 40% CAD, a behavior that did not occur in the G4 genotype.
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Palavras-chave
Compostos nitrogenados, Mecanismo de adaptação, Metabolismo antioxidativo, Seca, Vigna unguiculata L, Nitrogen compounds, Adaptation mechanism, Antioxidant metabolism, Drought