Abstract: To ascertain physiological and biochemical mechanisms of exogenous salicylic acid improving salt resistance of vegetable,cucumber(Cucumis sativus L.) was used to study effects of different concentrations exogenous salicylic acid on its morphogenesis,physiological and biochemical characteristic under 200 mmol·L^-1 NaCl stress with root injection and foliar spray.The results showed that exogenous salicylic acid significantly improved stem diameter,total dry mass and dry mass water content of cucumber seedlings, decreased the salt stress index, content of malondialdehyde (MDA) and permeation rate of electrolyte, increased contents of p roline ( Pro) , soluble sugar and activities of p rotected enzymes such as superoxide dismutase ( SOD) , peroxidase ( POD) and catalase (CAT) , also showed the op timum treatment concentration being 150 mg·L ^{- 1}. It is p roposed that exogenous salicylic acid as chemical activator could induce salt resistance, salt tolerance and decrease alleviate damage degree of salt stress of cucumber seedlings.

Key words: Cucumber, Salicylic acid, Salt stress, Physiological effects