Effects of Exogenous Nitric Oxide on Active Oxygen Metabolism in Cucumber Seedlings under NaCl Stress

The effects of sodium nitroprusside(SNP,an exogenous nitric oxide donor) on the active oxygen metabolism in cucumber seedlings under 100 mmol/L NaCl stress were studied by using nutrient solution culture.The results showed that NaCl stress could suppress the growth of cucumber seedlings,and reduce the activities of their protective enzymes superoxide dismutase(SOD) and peroxidase(POD).However,adding 0.1 mmol/L SNP could improve the growth of cucumber seedlings under NaCl stress,significantly alleviate the accumulation of ·O2-,obviously enhance the soluble protein content,and increase the activities of the protective enzymes(SOD,POD and CAT) in the leaves of cucumber seedlings.Especially,the activities of the isoenzymes of SOD and POD were induced by SNP.The above results indicated that exogenous nitric oxide could alleviate the oxidative damage caused by salt stress,which was achieved mainly by means of enhancing the anti-oxidative capability of cucumber seedlings.