Cadmium induced oxidative damage and antioxidant responses in roots of black gram [Vigna mungo (L.) Hepper]

A study was undertaken to investigate the effect of cadmium (Cd) on seed germination, growth and dry weight accumulation in black gram [Vigna mungo (L.) Hepper] cv. T-9, together with an analysis of the changes induced by Cd on the antioxidant enzyme status in the plant roots. Low concentrations of Cd were found to be slightly stimulatory while excess of Cd inhibited root and shoot growth, reduced dry matter accumulation. The activity of antioxidant enzymes varied with the concentration of Cd. A significant increase in malondialdehyde (MDA) content and stimulation of superoxide dismutase (SOD), peroxidase (PER), polyphenol oxidase (PPO) and phenylalanine ammonia lyase (PAL) was noted in seedlings exposed to 10, 50 and 100 μM Cd, while catalase (CAT) activity showed significant decrease above 10 M. Excess of Cd caused lipid peroxidation as well as modified the activity of defense enzymes SOD, PER, CAT, PPO and PAL.