荔枝果柄结构发育与落果的关系

在荔枝种子发育的各阶段，对落果与坐果果柄进行比较解剖观察，结果表明，落果果柄各组织、细胞的数量和分化速度均不及坐果果柄。花期和胚乳核分裂前期，花及幼果脱落与其果柄初生维管束和导管数量较少有关。在合子分裂期，果柄次生输导组织和中柱鞘纤维的产生，以及胚体形成期皮层和中柱鞘分化的石细胞，均可加强果柄机械力度。果熟期由于果柄周皮形成和内部结构完善，落果数量减少。

The Relationship between Structures of Fruit Stalks and Fruit Dropping in Litchi

Numbers and the differentiation speed of tissues and cells of fruit stalks at different stages during seed development in litchi were observed by means of comparative anatomy. The dropping of flowers and young fruits at flowering period and prophase of the division of endosperm related with the less number of primary vascular bundles and vessels of flower stalks and fruit stalks. At the division stage of zygotes,the emergency of secondary transportation tissues and pericycle fibers,the formation of embryoes,and the differentiation of sclerid in cortex and pericycle,were favourable for enhancing mechanical strength of fruit stalks. At fruit mature stage, the number of dropt fruits could be controlled as the formation of periderm and the perfection of innal structures of fruit stalks. According to these results,it seems to be possible to make the increase of fruit setting rate by applying exohormones to regulate the structures of fruit stalks.