51. Antioxidant defence system and oxidative damages in Rice seedlings under heatstress
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Abstract
Impact of climate change showed heat stress most severely affecting crop growth and yield worldwide. In current study, oxidative damages and response of antioxidant enzymes were compared in 4 rice cultivars (IR-6, IR-8, K-95 and Sada Hayat). These varieties were exposed to heat (42±2 ºC) stress at seedling stage. After 72 h, stressed plants transferred to normal temperature for recovery treatments. Oxidative stress damages were quantified through analysis of hydrogen peroxide (H2O2) and malondialdehyde (MDA) content. Effect of heat stress on antioxidant enzymes activities were determined by quantitative analysis of ascorbate peroxidase (APX) and catalase (CAT) enzymes. With increasing oxidative stress significant proline accumulation was detected in rice cultivars and K-95 had maximum proline among the group. Significant increment of MDA and hydrogen peroxide (H2O2) content was found in as compared to others. CAT and APX showed significantly declined activity in Sada Hayat and IR-8 under heat stress condition however K-95 showed maximum activity. These findings suggesting that (i) K-95 is comparatively thermotolerant cultivar (ii) thermo-tolerance in rice is closely related to efficient antioxidant enzyme defence system.
Keywords: Oxidative stress; Antioxidants; Lipid peroxidation; Thermotolerance Rice; Enzymes