文冠果花性别分化及花药内淀粉动态

本文在对文冠果花芽分化和成花过程进行外部形态及细胞学观察的基础上,对其花性别分化即孕花与不孕花的发育情况进行了比较.实验表明:在蕾前期两种花在形态及解剖构造上未见差异,但在单核小孢子进行第一次有丝分裂后,差异日趋明显.孕花中雌蕊发育正常,雄蕊发育缓慢,花丝短,绒毡层消失比较晚,花药不开裂,花粉无萌发力,形成败育的雄蕊.而不孕花雄蕊发育正常,子房却在单核期停止发育,迅速退化.影响文冠果花性别分化的主要因素是与树体的营养状况密切相关.孕花中败育的花药较早就出现淀粉粒贮藏不足,这可能与子房和雄蕊对营养物质的竞争有关,小孢子因得不到足够的营养物质而败育.

The Floral Sex-Differentiation of Xanthoceras sorbifolia and the Dynamics of Starch in Anthers

Anatomical and histochemical studies in the floral bud differentiation and development process of Xanthoceras sorbifolia Bunge have been carried out in this paper and the processes of floral sex-differentiation-the development of male and female flowers of Xanthoceras sorbifolia Bunge-have been compared. It has expressed that there is not any difference in morphology and structure between two types of flowers in the early stage of floral sex-differentiation. Distinct changes in the flowers of two types become noticeable only after the first mitosis of microspore. In pistillate flower, the pistil is normal, but the stamen develops slowly, filament is short in length; the tapetum disappears late; the anther is undehiscent; pollen cannot germinate. While, in the male flower, the stamen develops normally, the ovary stops developing in uninucleat stage of embryo sac and degenerates speedily. It is hypothesized that the main factor affecting floral sex-differentiation is closely related to the nutrient situation of tree and floral bud. In the pollen of the pistillate flower, less starch accumulation appears than in the pollen of the male flower during the whole period of microsporogenesis. This could be related to nutritive competition between ovary and stamen. The pollen's abortion is due to the shortage of nutrient material and energy.