Effects of calcium on antioxidant enzymes activities of cucumber seedlings under salt stress.

The effects of Ca2+ on the changes of soluble protein,malondialdehyde(MDA)contents, superoxideanion(■)production rate,superoxide dismutase(SOD),peroxidase(POD)and catalase (CAT)activities in cucumber(Cucumis sativus L.‘Jinchun 2’)seedlings under 50 mmol · L-1 NaCl salt treament was studied. The results showed that the contents of soluble proteins and MDA,■ production rate,antioxidant enzyme activities were higher in salt stress than control;In salt + Ca2+ treatment,soluble proteins content,SOD,POD and CAT activities increased,while MDA content and ■ production rate decreased. Under salt stress and salt + Ca2+,the MDA content,■ production rate raised,while soluble proteins content,SOD,POD and CAT activities declined. The results indicated that Ca2+ could raise the activities of antioxidant enzymes and decrease the membrane lipid peroxidation for cucumber seedlings, which could alleviate the damage of salt stress and improve the salt stress adaptability of cucumber seedlings.