Oxidative Stress Damage and Antioxidant Activity in 4 Cultivars of Peanut (Arachis hypogaea l.) under Drought Stress

This study evaluates the extent of cellular damage caused due to water stress and the activity of 4 significant antioxidant enzymes to counteract the severity of drought stress in 4 cultivars of peanut, with varying degrees of drought tolerance. Drought stress was imposed by with holding irrigation to the 20 - day old seedlings for 10, 15 and 20 days. Leaf samples were collected on 31^st, 36^th and 41^st days from these plants along with their controls. The results indicated that ICGV 91114 was the most drought tolerant variety followed by ICGS 76 and J 11 while JL 24, the most drought susceptible. Lipid peroxidation and protein carboxylation, the measures of stress damage were maximum in 20 day stressed plants of JL 24 and least in ICGV 91114. The activities of SOD, APX and GR were maximum in 15 day stressed plants of ICGV 91114, ICGS 76 and J 11 cultivars while the activity of CAT was maximum in 20 day stressed plants of all the 4 cultivars. These results indicate that an enormous increase in superoxide levels in plants during stress disturbs all vital biomolecules, if not scavenged. Hence, a complex defense mechanism evolved by plants involving various antioxidant enzymeslike CAT, SOD, APX and GR work in coordination to efficiently combat the danger posed by deleterious ROS.