Abstract: The mitigation of toxic effect of Cd²⁺ on Trapella sinensis Olive by exogenous Pro was studied. The results showed that when treated with single 3 mg·L^-1 Cd²⁺ for 5 d,the Pro content increased,chlorophyll and soluble protein content dropped,the balance of antioxidase(SOD,POD,CAT) was broken and their activities decreased,MDA content,O^-₂ generation rate increased in T. sinensis Olive.When different conditions of Pro was added into the solution,Pro content dropped,the degradation of chlorophyll and soluble protein was alleviated,the activities of SOD and POD raised,the activity of CAT returned to normal level,the balance of antioxidase was rebuilt,the activity of antioxidase was enhanced, O^-₂ generation rate was dropped,and accumulation of MDA was reduced in comparison with single Cd²⁺ treatment. As a result, exogenous Pro can enhance the resistance of plants to heavy metal stress.The optimum dose of Pro to Cd²⁺ in T. sinensis Olive was ranged from 40~60 mg·L^-1.

Key words: Cd²⁺, Pro, Trapella sinensis Olive