Effect of Cadmium Stress on Active Oxygen Metabolism in Germinated Soybean Seeds

Effect of active oxygen metabolism in germinated soybean seeds under cadmium stress were studied with pot culture experiment. The results showed that compared with the control, under the treatment of lower concentration cadmium, there were no significant differences in generative rate of superoxide radical (O2-), H2O2 content in germinated soybean seeds during the beginning period (1~3 d). Under the treatment of lower concentration cadmium, the activities of superoxide dismutase (SOD), catalase (CAT) were increased significantly on the 3rd day, while, they decreased and malondialdehyde (MDA) content and membrane electrolytic leakages increased significantly after four days. Compared with the control, under the treatment of higher concentration (10, 30, 50 μmol·L-1) cadmium, the generative rate of O2-, H2O2 content, MDA content, membrane electrolytic leakages increased significantly and the activities of SOD, CAT decreased during 2~6 d. Cd2+ stimulated peroxidase(POD)activity and the activity increased gradually with the increase of Cd2+ concentrations. Injury effects of Cd2+ stress on active oxygen metabolism in germinated soybean seeds could aggravate the membrane lipid peroxidation.