Effects of cadmium stress on antioxidant responses of Vigna radiate L.Wilcziek

The current study evaluated the effects of cadmium stress on the antioxidant responses of Vigna radiata L. Wilcziek. The treatments consisted of 0, 25, 50, 75, and 100 ppm of CdCl2 2H2O. Seeds were placed in plastic trays and watered with distilled water. After 24 hours, the seeds germinated, and then they were transferred to pots. We irrigated each pot with their desired treatment solution until the end of the growth phase. A sampling of mature leaves at the flowering time was done. The concentration of cadmium in soil and other tissues of the plant, the level of leaves soluble proteins, ascorbate peroxidase (APx) and peroxidase enzymes (POD), total antioxidant capacities (TAC), and concentration of hydrogen peroxide (H2O2 ) in the samples were measured and compared to control. The lowest level of soluble protein (73.75±6.8 mg L-1 ) was observed in the 50 mg Cd/L treatments. The maximum rate of H2O2 (1.82±0.06 μM g-1 frw) and APx (0.83±0.04 U gfrw-1 ) activity was measured in treatment of 25 mg Cd/L and the lowest was observed in the treatment of 100 mg Cd/L (1.16±0.08 μM g-1 frw and 0.19±0.02 U gfrw-1 , respectively). The highest and lowest level of POD was observed in the treatment of 75 mg Cd/L (1.93±0.03 U gfrw-1 ) and 100 mg Cd/L (0.12±0.02 U gfrw-1 ), respectively. The Mung bean plant has a resistance to cadmium stress even up to 100 ppm. This resistance appears to be due to the high total antioxidant capacity of the V. radiata. Hereupon, mung bean can provide a safe culture for cadmium-contaminated environments.