Ferrous Chloride and Sodium Ascorbate Alleviate Pb Toxicity in Rice Seedlings by Modulating the Activity of Antioxidative Enzymes

When seedlings of an Indica rice cultivar HUR-105 were raised for 8 days in hydroponics in Yoshida nutrient solution containing 800 μM Pb(NO₃)₂, it was observed that Pb treatment caused reduction in height and fresh weight, and increase in the activity of antioxidative enzymes such as superoxide dismutase, catalase and ascorbate peroxidase. The reduction in height and fresh weight was greater with increase in Pb treatment duration. Pb treated seedlings showed the elevated level of antioxidative enzymes activity at 8^th day as compared to 4^th day in the roots and shoots of the seedlings. When FeCl₂ and sodium ascorbate were added in Pb containing growth medium, a noticeable alleviation of Pb toxicity was seen in correlation to growth parameters and antioxidative enzymes activity in both roots and shoots of rice seedlings. Results suggest that both FeCl₂ and sodium ascorbate have high potential to alleviate Pb toxicity in rice seedlings.