Abstract: Cerous relieved the increase of membrance penetrability (MP), the decrease of soluble protein content and chlorophyll a/b value, the accumulation of O₂· andMDA in Spirodela polyrhiza L.leaves under stress of Cu²⁺.Compared with those of single Cu²⁺ treatment, 20 mg/L Ce improved the activities of superoxide dismutase( SOD), catlase(CAT)and peroxidase(POD), the content of Car and AsA to a certain extent.The results implied that Ce could enhance the abilities of reactive oxygen species(ROS)scavenging system in the plant, therefore increase the resistance and tolerance to Cu stress.

Key words: Cu, Ce, Spirodela polyrhiza L., resistance