Submergence tolerance in rice: a physiological investigation
1997
Ella, E.S. | Laureles, E.V. | Valdez, A.P. | Setter, T.L. (International Rice Research Inst., P.O. Box 933 Manila (Philippines). Agronomy, Plant Physiology and Agroecology Div.)
Limited oxygen diffusion during complete submergence of plants is a major growth-limiting factor because oxygen is required for energy production. In the absence of oxygen, alcoholic fermentation generates the energy necessary for either maintenance or growth processes, resulting in plants with submergence tolerance or elongation ability. Optimization of maintenance vs. growth processes affects survival because elongation growth competes for energy and carbohydrates reserves which are essential for maintenance processes during submergence. This study (1) evaluated the importance of some physiological traits in seedlings of five rice cultivars exposed to complete submergence and (2) presented information to elucidate the mechanism of submergence tolerance in rice. The carbohydrate content before submergence, elongation growth and activities of enzymes in alcoholic fermentation and glycolysis during submergence, plant survival after submergence, and other relevant parameters were measured. There was high correlation between seed carbohydrate content and survival in 2-wk-old seedlings (r square = 0.80-0.90). Reduced elongation growth during submergence increased survival in 4-wk-old seedlings (r square = 0.81). Enzyme activity data suggested that pyruvate decarboxylase and phosphofructokinases may limit submergence tolerance
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