Oxidative stress induced by copper in sunflower plants

The toxic effect of copper was evaluated in sunflower plants by means of ro ot elongation, lipid peroxidation and antioxidative enzyme activities. Plan ts were grown under controlled environmental conditions in hydroponic cultu re for two weeks and exposed to different copper concentrations for an addi tional week. Determinations were performed in both roots and leaves. From t he results of the root elongation test, a copper concentration of 10 mu M w as found to be toxic for sunflower plants causing lipid peroxidation and, t hus, oxidative stress. Antioxidative enzymes (peroxidase and superoxide dis mutase) responded at lower, nontoxic copper concentrations.