EFFECTS OF CUPRIC SULFATE ON THE SEED GERMINATION AND SEEDLING GROWTH OF LOQUAT

The effects of cupric sulfate on seed germination, plant growth, contents of photosynthetic pigments, peroxidase (POD) and polyphenol oxidase (PPO) activities in leaves and roots of loquat (Eriobotrya japonica Lindl.) cv. ‘Jiefangzhong’, the main loquat cultivar in Fujian, were studied. The results showed that cupric sulfate at a low concentration (2.5 mg L^-1) increased the seed germination rate by 3.69%, while high concentrations at 7.5 mg L^-1 and 12.5 mg L^-1 inhibited the seed germination by 10.14 and 17.05%, respectively. The height of seedlings treated with 2.5 mg L^-1 cupric sulfate was lower than that of control, with green and thick leaves and well-growing roots. When treated with 7.5 mg L^-1 and 12.5 mg L^-1 cupric sulfate, the heights of seedlings were still lower, but with yellowish, smaller and thinner leaves and weaker roots. The decrease in chlorophyll content was attributed to the decline of chlorophyll a. The POD and PPO activities in the seedlings treated with cupric sulfate below 7.5 mg L^-1 were increased, while those treated with the concentrations above 12.5 mg L^-1 declined and the vegetative growth was inhibited.