The Effect of Paclobutrazol on the Growth and Development of Walnut and Its Physiological Mechanism

In this paper, the effect of paclobutrazol on the growth and development of walnut and its physiological mechanism were studied. The results showed that paclobutrazol (1000~2000 ppm) could significantly depress the growth of shoot (decreased the length and thickness of shoots), reduce the trunk diameter and single leaf area, increase the number of nuts and greatly raised the yield per plant. The physiological effects of paclobutrazol on walnut were as follows; increase the concentrations of chlorophyll, soluble sugar and protein in leaves, reduce the contents of GA3, IAA and ABA in shoot tips or buds, and had no influence on the quality of nuts. The paper also discussed the possible mechanism of paclobutrazol affecting walnuts.