荔枝三种结实类型内源激素的平衡与坐果机理

Endogenous Hormone Balance in Three Types of Litchi Fruit and Their Fruit Set Mechanism

首次引入内源激素平衡[(1AA+GAs+CTK)/ABA]概念,比较分析了荔枝三种类型果实(大核、小核、无核)内源激素平衡的动态变化;揭示了无核果在花后3d相对高水平的生长促进类激素(IAA+GAs+CTK)及花后ABA水平的持续下降是其具有单性结实能力的主要原因;同时,揭示了坐果期低水平的IAA、GAs及相对较低的(IAA+GAs+CTK)/ABA值是小核品种严重生理落果的主要原因;并比较了荔枝果实各组成部分(果皮、假种皮、种子)内源激素平衡的差异,认为胚的正常发育对维持荔枝果实后期的生长发育有重要意义,是大核品种后期生理落果较少的内部生理基础。

The concept of endogenous hormone balance [(IAA + GAs + CTK)/ABA]was initially used in this article. Results of the comparative study on the dynamics of the hormone balance of the three types of litchi fruit (normal seed,aborted seed and seedless) showed that the relatively higher level of growth promoters (IAA + GAs + CTK) and the continued decline in level of ABA after anthsis in seedless cultivar were the major reason for its naturally parthnocarpic capability; the lower content of IAA,GAs and lower level of (IAA + GAs + CTK)/ABA during fruit set in aborted-seed cultivar and normal seeded cultivars cause the serious fruit drop. Moreover .the differ-ence in endogenous hormone balance among fruit component (pericarp,aril,seed) was studied. It was suggested that the normal development of embryo is important to the later stage growth and development of litchi fruit and the internal physiolgical base of less serious fruit drop in normal seeded cultivar. The results obtained were discussed in relation to fruit set mechanism.