苹果幼树生长发育中应用多效唑的研究

多效唑(PP333)在二年生‘富士’和一年生‘秦冠’幼树上的应用效果表明,根施1～15g/株当年和后两年营养生长受到显著抑制,新梢生长置下降63%～97%;节间长度缩短35%～45%;干径和主枝径增粗率下降35%～85%;‘富士’第二年(3年生)和第三年(4年生)树高、冠径下降45%～55%、70%～75%;根长下降55%～60%.根量减少10%～70%;根皮率提高15%～35%,叶面积下降30%～42%;叶绿素含量提高10%～15%;光合强度提高47%～50%,部分幼树次年和第三年开花(16%和40%);幼树越冬能力提高,抽干率和抽干指数分别下降85%～97%和80%～86%,但顶芽越冬后有10%～15%枯死.适宜的使用时期是新梢长度5～10cm 时(6月中旬).

STUDIES ON THE EFFECTS OF PACLOBUTRAZOL ON THE GROWTH AND DEVELOPMENT OF YOUNG APPLE TREES

It is reported in this article that PP333 application effect in two-year-old‘Fuji’& one-year-old‘Qinguan’apple trees.It was discovered thatPP333 is a severe growth retardant.1—15g application to the root madethe growth retarded seriously in the first & the year after next.The reduction of growth increment of new growth was 63%—97%.Theinternodal length reduction was 35%—45%.The reduction of the thicknessof central leader & leader branch was 35%—85%.The reduction of theheight & crown of the three-year-old and four-year-old‘Fuji’apple treewas 45%—55%,70%—75% respectively.The reduction of root length andradical number was 55%—60%,10%—70% respectively,while the incrementalextent of root-phloex ratio was 15%—35%.The reduction of leaf-areawas 36%—42%.The incremental extent of chlorophyll and photosynthesisintensity was 10%—15%,47%—50% respectively.Some of the young appletrees were in bloom next year and the year after next when PP333 wasapplied(16% & 40% respectively).The winter hardiness of young appletrees was increased.The redaction extent of the rate and index of winterdesiccation was 85%—97%,80%—86% respectively.However there was a10%—15% phyllogen blight when winter is over.The proper PP333 applica-tion period is in the middle of June when new growth is 5—10cm long.