Effect of exogenous cytokinins on growth,activities of antioxidative enzymes and proline content in corn seedlings (Zea Mays L.) under cadmium stress
细胞分裂素类物质对镉胁迫下玉米幼苗生长和抗氧化酶活性及脯氨酸含量的影响

The effects of spraying two cytokinins, 6-benzylaminopurine (6-BA) and kinetin (KT), on the growth, the contents of chlorophyll and proline and cadmium, as well as the activities of antioxidant enzymes such as superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT) in the leaves of corn seedlings under cadmium stress were studied by solution culture experiments. The results showed that spraying 6-BA and KT increased the biomass and the contents of chlorophyll, proline and cadmium, while it decreased the content of malondialdehyde (MDA) in corn leaves. The treatments also promoted the increase of the enzyme activities of CAT and POD, while they did not significantly influence the activities of SOD in corn leaves. The results suggest that exogenous cytokinins could alleviate the toxicity of cadmium to corn seedlings by keeping the stability of chlorophyll, enhancing the H2O2 scavenging systems through accumulating more proline, and improving the activities of POD and CAT in plants. The alleviation effects increased with the increase of spraying concentrations from 0 to 20 mg·L-1 for 6-BA, while the optimal alleviation effect was obtained at a concentration of 70 mg·L-1 for KT.