The present study was conducted to evaluate the phytotoxic effects induced by hexavalent chromium (Cr) on germination and antioxidant response in Indian wild rice (Oryza nivara and Oryza rufipogon). After exposure to varying concentration of Cr, two varieties of wild rice O. nivara and O. rufipogon showed significant changes in growth and physiological parameters. Higher concentration of chromium resulted in significant reduction of germination, fresh weight, dry weight and dry matter accumulation in both the wild rice seedlings compared to the control plants. In low concentration of Cr (25; 50 μM) the activities of antioxidative enzymes were significantly increased in both the varieties over control and the activities were significantly decreased under high concentration of Cr (75; 100 μM). The results from the present experiments suggest that high concentrations of Cr caused oxidative damage as evidenced by increased anti-oxidative enzymes and the induction of antioxidative enzymes could be the reason for tolerating higher levels of metals by wild rice. The findings suggest that phytoremediation of Cr from soil by application of weeds like Indian wild rice.

Keywords: Antioxidative enzymes; Chromium; Phytoremediation; Wild rice;