PP333对山楂幼树新梢生长、干径增粗和树冠体积的抑制作用,经用新复极差( SS R)法检验,差异均达到显著和极显著水平。特点是缩短新梢节间,抑制新消伸长,新梢叶片数随浓度的加大而逐渐减少。新梢叶片数过少,必然影响叶面积,但由于减少了新梢生长量,也相对的减少了用于枝干的养分 PP333 inhibited the shoot growth, stem thickening and canopy volume of young hawthorn seedlings. The results of SSR test showed that the differences were significant and highly significant. The feature is to shorten the shoots of new shoots and restrain the elongation of new shoots. The number of shoots of young shoots gradually decreases as the concentration increases. The number of shoots is too small, will inevitably affect the leaf area, but due to reduce the growth of shoots, but also relatively reduce the nutrients used in the branches