Effect of excess copper on rice leaves: evidence for involvement of lipid peroxidation

Lipid peroxidation in relation to senescence of detached rice leaves caused by excess copper was investigated. Excess copper, which was found to promote senescence, increased the level of lipid peroxidation but not the level of H2O2. Catalase and glutathionine reductase activities were reduced by excess copper. Superoxide dismutase and ascobate peroxidase activities did not seem affected by excess copper. Free radical scavengers inhibited excess copper-promoted senescence and at the same time inhibited excess copper-induced lipid peroxidation, suggesting that lipid peroxidation induced by excess copper is mediated through free radicals.