Efeitos do estresse induzido por polietileno glicol (PEG 6000) em feijoeiro (Phaseolus vulgaris L.)
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Data
2001-03
Autores
Guimarães, Vandeir Francisco [UNESP]
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Editor
Universidade Estadual Paulista (Unesp)
Resumo
Objetivando estudar os efeitos do estresse induzido por PEG 6000 no feijoeiro (Phaseolus vulgaris L.), através da avaliação de relações hídricas, trocas gasosas e metabolismo de compostos nitrogenados (prolina e poliaminas), foi conduzido um experimento em casa de vegetação, no Departamento de Botânica da UNESP, Campus de Rubião Júnior, em Botucatu, SP. Foram avaliados os cultivares Manteigão Fosco e Pérola e linhagem BAT 477 em dois regimes hídricos: sem estresse e com estresse, em um arranjo fatorial, em blocos casualizados, com quatro blocos. O estresse foi imposto no início da fase reprodutiva (32 DAT), pelo aumento da concentração relativa de PEG 6000 na solução nutritiva devido à perda de água por evapotranspiração. CRA, Ψhf, A, gs, E, Ci e teores de prolina e poliaminas nas folhas, foram determinados durante o período de estresse e reidratação. Medidas de trocas gasosas foram feitas com um IRGA 6200 da LI-COR, as 9 e 15 horas. Parâmetros biométricos foram determinados após a imposição do estresse em ambas as plantas sem e com imposição de estresse. O CRA foi mais eficiente indicador do status hídrico da planta do que o Ψhf, nas condições de estudo. O estresse reduziu drasticamente A, gs e E, levando a aumentos na EUA nos níveis iniciais de estresse. Ci foi um eficiente indicador de inibição mesofílica na fotossíntese em níveis mais elevados de estresse. O cultivar Manteigão Fosco foi mais sensível ao estresse induzido por PEG 6000, sendo o primeiro a apresentar sintomas visuais nas folhas, caracterizados por descolorações internervais que posteriormente evoluíram a necroses. Reduções em CRA, A, gs e E ocorreram de forma mais intensa eprecoce neste cultivar, que apresentou maior acúmulo relativo de prolina nas folhas, em reposta à deficiência hídrica. Os teores de poliaminas não... .
One assay was carried out, in greenhouse conditions, to study the effects of induced stress by PEG 6000 in bean (Phaseolus vulgaris L.), by the evaluation of water relation, gas changes and metabolism of nitrogen compounds (proline and polyamines). The assay was conducted in the Botany Department of the College of Agronomic Science – UNESP – Botucatu, state of São Paulo. The cultivars evaluated were Manteigão Fosco and Perola and the inbred BAT477 under two water regimes: with and without stress in a factorial design, in randomized blocks with four replications. The stress was imposed at the beginning of the reproductive stage (32 DAT) increasing of the relative concentration of PEG 6000 in the nutritive solution proportional to the water loose by evapotranspiration. RWC, Ψhf, A, gs, E, Ci and amounts of proline and polyamines in the leaves were measured during the stress period and re-hydration. Measurements of gas exchange were done with an IRGA LI-COR (Li-6200), at 9 and 15 h. Biometric parameters were determined after imposition of the stress in both plants with and without stress. The RWC was the most efficient indicator of the plant water status than the Ψhf, in the study. The stress reduced drastically A, gs and E, increasing the WUE in the initial levels of stress. Ci was an efficient indicator of mesofilic inhibition of photosynthesis under severe stress. The cultivar Manteigão Fosco was the most sensitive to stress induced by PEG 6000 and it was the first to show visible symptoms on leaves characterized by internerval discoloration that became necrotic. The reduction in RWC, A, gs and E began early and was higher in this cultivar, which a greater accumulation of proline in the leaves, of stressed plants. The amounts of polyamines didn’t show direct correlation with the stress imposition occurring a slight accumulation... (Complete abstract, click electronic address below).
One assay was carried out, in greenhouse conditions, to study the effects of induced stress by PEG 6000 in bean (Phaseolus vulgaris L.), by the evaluation of water relation, gas changes and metabolism of nitrogen compounds (proline and polyamines). The assay was conducted in the Botany Department of the College of Agronomic Science – UNESP – Botucatu, state of São Paulo. The cultivars evaluated were Manteigão Fosco and Perola and the inbred BAT477 under two water regimes: with and without stress in a factorial design, in randomized blocks with four replications. The stress was imposed at the beginning of the reproductive stage (32 DAT) increasing of the relative concentration of PEG 6000 in the nutritive solution proportional to the water loose by evapotranspiration. RWC, Ψhf, A, gs, E, Ci and amounts of proline and polyamines in the leaves were measured during the stress period and re-hydration. Measurements of gas exchange were done with an IRGA LI-COR (Li-6200), at 9 and 15 h. Biometric parameters were determined after imposition of the stress in both plants with and without stress. The RWC was the most efficient indicator of the plant water status than the Ψhf, in the study. The stress reduced drastically A, gs and E, increasing the WUE in the initial levels of stress. Ci was an efficient indicator of mesofilic inhibition of photosynthesis under severe stress. The cultivar Manteigão Fosco was the most sensitive to stress induced by PEG 6000 and it was the first to show visible symptoms on leaves characterized by internerval discoloration that became necrotic. The reduction in RWC, A, gs and E began early and was higher in this cultivar, which a greater accumulation of proline in the leaves, of stressed plants. The amounts of polyamines didn’t show direct correlation with the stress imposition occurring a slight accumulation... (Complete abstract, click electronic address below).
Descrição
Palavras-chave
Stress (Fisiologia), Fotossintese, Poliaminas, Feijão comum, Plantas - Transpiração
Como citar
GUIMARÃES, Vandeir Francisco. Efeitos do estresse induzido por polietileno glicol (PEG 6000) em feijoeiro (Phaseolus vulgaris L.). 2001. xii, 105 f. Tese (doutorado) - Universidade Estadual Paulista, Faculdade de Ciências Agronômicas, 2001.