Effects of Zinc Levels on Growth and Development and Physiological Metabolism in Pineapple
Seven levels of zinc (0, 0.001, 0.002 5, 0.005, 0.01, 0.02, 0.04, 0.08 mg/L) were applied in the hydroponic culture to study the effect of zinc on its growth, development and physiological metabolism in pineapple. The results showed adequate levels of zinc improved but high levels of zinc inhibited the growth and development of pineapple. In a give range of zinc levels adequate level of zinc increased the activities of CAT, POD, SOD and PPO in pineapple leaves, but high level of zinc resulted in high content of MDA and O2-. in the leaves. Only excessive levels of zinc inhibited the growth of pineapple. Adequate levels of zinc increased the content of chlorophyll, the rate of photosynthetic, the synthesis and accumulation of carbohydrate.