红富士苹果幼树生长旺,尤其在河北省中南部春季干旱夏季多雨,枝条在一年中有多次生长,且停长晚,枝条发育不充实,越冬困难,因此,如何控制幼树长势,特别是秋梢生长,增加树体贮藏养分,是目前该地区急待解决的主要问题。多效唑(PP_(33))是一种新型的植物生长调节剂,它能抑制赤霉素的生物合成,从而抑 Young Fuji apple trees grow vigorously, especially in central and southern Hebei Province. In spring and summer, it is rainy in summer, with branches growing many times in one year, stopping growing for a long time, branches are not well developed and winter is overwintered. Therefore, how to control the growth of young trees, In particular, the growth of autumn shoots and increased storage of tree nutrients are the major problems to be solved urgently in the region. Paclobutrazol (PP_ (33)) is a novel plant growth regulator that inhibits the biosynthesis of gibberellins