Effects of exogenous melatonin on antioxidant properties of kiwifruit seedling leaves under copper stress

The one-year-old wild Actinidia deliciosa seedlings were used as materials, by root irrigation of 0.1 mu mol.L-1 MT solution and 15 mu mol.L-1 copper sulfate solution, to investigate the effects of exogenous melatonin on antioxidant properties of kiwifruit leaves under copper stress. The results showed that the relative electrolyte leakage, MDA content of kiwifruit seedlings gradually increased, while H2O2 content, SOD activity, POD activity and CAT activity increased first and then decreased under copper stress. With the application of exogenous melatonin, the relative electrolyte leakage and the accumulation of H2O2 and MDA were effectively reduced in kiwifruit seedlings leaves under copper stress, while the soluble protein content and the activity of SOD, POD and CAT were increased. The results indicated that melatonin could reduce the toxicity of copper stress on kiwifruit seedlings and improve the resistance of kiwifruit.