Effects of selenium on the antioxidation of root of Cardamine sp. from Enshi

To determine the physiological impact of selenium on the root of Cardamine sp., a Se-hyperaccumulator at Enshi, the plant was cultured in complete nutrient solution containing 0, 15, 30, 45, 60, 75, or 90 mg·L^-1 Na₂SeO₃, and the selenium content and the antioxidant activity in root were investigated. The results showed that Se addition can significantly increase selenium content, with the maximal level of 726.78 μg/g at Se concentration of 60 mg/L. The enzymatic activity of GSH-Px(glutathione peroxidase), CAT(catalase), POD(peroxidase) enhanced at Se addition level of 30-90 mg/L, with the highest activity at 60-75 mg/L Se concentration. The significant increase of enzymatic activity for SOD(superoxide dismutase) than control only occurred in the Se concentration of 75 mg/L. When Se concentration was 15-90 mg/L, there was only minimal MDA(malondialdehyde) production in root, and there were significant differences comparing to the control. Therefore, when Cardamine sp. is cultured in the complete nutrient solution, the antioxidant enzyme activity in root can be promoted and its ability for lipid peroxidation can be improved at 30-75mg/L of Se concentration.