Effect of the simulated acid rain on the metabolism of the activated oxygen was studied with cotton cotyledon disc. It was observed that acid rain resulted in decreasing the activities of protecting enzymes and increasing the strength of lipid peroxidation of membrance in the discs. Superoxide dismutase (SOD) might play an important role in controlling the lipid peroxidation of membrane in discs. Application of free radical scavengers could inhibit membrane lipid peroxidation. and maintain a higher level of...