Modulation of antioxidant defence system for arsenic detoxification in Indian mustard.

This study investigates the modulation of antioxidant defence system of Indian mustard (cv. Pusa Jai Kisan) against the arsenic (As)-induced toxicity in 20-day-old plants, exposed to 5 and 25 microM As for 96 h in hydroponic culture. Reduction in plant growth, measured in terms of root and shoot dry weights, was insignificant with 5 microM, but highly significant with 25 microM As treatment. Shoots accumulated more As than roots. The extent of oxidative stress in the leaves was measured as the rate of lipid peroxidation. The As treatments significantly increased the activities of antioxidative enzymes (superoxide dismutase, ascorbate peroxidase and glutathione reductase) and the contents of antioxidants metabolites (glutathione and ascorbate), the increase being dependent on exposure time. Increase in the activity of catalase was not significant, however. In conclusion, Indian mustard was able to detoxify the low As level through induction of antioxidant defence mechanism.