Abstract:

Heavy metal chromium markedly inhibits plant growth and development. Although extensive studies have been conducted on the effects of chromium on other plant species such as wheat, the mechanisms of effects of chromium on Siraitia grosvenorii remain unknown. In this study, we analyzed the responses of Siraitia grosvenorii to various levels of Cr6+ (0, 50, 100, 150 and 200μmol?L-1) at physiological and biochemical levels . The results showed that the contents of chlorophyll, protein, soluble sugar, activity of superoxide dismutase(SOD) and catalase were significantly decreased with increasing concentrations of chromium; the levels of peroxidase (POD) activity were increased at low concentrations of chromium and decreased when the plants were exposed to high concentrations of chromium. By contrast, the contents of proline and malonaldehyde(MDA)were substantially increased with increasing concentrations of chromium in the growth medium. The results indicate that chromium causes damage of the celluar membrane system and subsequent growth inhibition of Siraitia grosvenorii and proline and ROS signaling may play important roles in plant response to chromium.