Pb-Stress Induced Oxidative Stress Caused Alterations in Antioxidant Efficacy in Two Groundnut ( Arachis hypogaea L.) Cultivars

Abstract

Lead (Pb) is an important environmental pollutant extremely toxic to plants and other living organisms including humans. To assess Pb phytotoxicity, a pot culture experiment was carried out using two groundnut cultivars (Arachis hypogaea L. cultivar K6 and cultivar K9) on plant growth, ROS levels, lipid peroxidation, and antioxidant metabolism using biochemical, histochemical methods. Plants were grown in pots for 14 days, in the botanic garden, and subjected to Pb-stress (0, 100, 200, 400 and 800 ppm) by adding Pb (NO3)2 solution and further allowed to grow for 10 days. The results showed that cultivar K6 registered lower Pb accumulation than cultivar K9, however, localization of Pb was greater in roots than leaves in both groundnut cultivars. The Pb-stress results in an increase in free radicals (O2●− and H2O2) generation in both groundnut cultivars, but more significantly in cultivar K9 than K6. Pb-stress also caused significant changes in the rate of peroxidation as shown in...