Effect of Chitosan on Relieving Chilling Injury of Cucumber Seedling

0.5 mg/ml,1 mg/ml,2 mg/ml and 4 mg/ml of Chitosan was sprayed on cucumber seedlings respectively, and then the cucumber seedlings were treated at 5 ℃ for 2 days respectively, in order to study the influence of chitosan on cucumber seedlings under freezing stress. The main results were the content of chlorophyll was increased and the activity of SOD, POD and CAT were enhanced too. In addtion,the content of MDA were reduced. It was concluded that chitosan can effectively alleviate the damage of the freezing stress to cucumber seedings.The optimum concentration of chitosan was 1mg/ml.