Drought Induces Oxidative Stress and Enhances the Activities of Antioxidant Enzymes in Growing Rice Seedlings |
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Authors: | Pallavi?Sharma Email author" target="_blank">Rama?Shanker?DubeyEmail author |
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Institution: | (1) Department of Biochemistry, Faculty of Science, Banaras Hindu University, 221005 Varanasi, India |
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Abstract: | When rice seedlings grown for 10 and 20 days were subjected to in vitro drought stress of −0.5 and −2.0 MPa for 24 h, an increase in the concentration of superoxide anion (O2.−), increased level of lipid peroxidation and a decrease in the concentration of total soluble protein and thiols was observed
in stressed seedlings compared to controls. The concentration of H2O2 as well as ascorbic acid declined with imposition of drought stress, however glutathione (GSH) concentration declined only
under severe drought stress. The activities of total superoxide dismutases (SODs) as well as ascorbate peroxidase (APX) showed
consistent increases with increasing levels of drought stress, however catalase activity declined. Mild drought stressed plants
had higher guaiacol peroxidase (GPX) and chloroplastic ascorbate peroxidase (c-APX) activity than control grown plants but
the activity declined at the higher level of drought stress. The activities of enzymes involved in regeneration of ascorbate
i.e. monodehydroascorbate reductase (MDHAR), dehydroascorbate reductase (DHAR) and glutathione reductase (GR) were higher
in drought stressed plants compared to controls. Results suggest that drought stress induces oxidative stress in rice plants
and that besides SOD, the enzymes of ascorbate-glutathione cycle, which have not been studied in detail earlier under stressful
conditions, appear to function as important component of antioxidative defense system under drought stress. |
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Keywords: | Antioxidative enzymes Drought stress Lipid peroxidation Oryza sativa Oxidative stress Superoxide |
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