Abstract: In order to explore the division process of endosperm and its influencing factors, the division ways of free nuclei and cytological characters of endosperm in rice were studied with light and transmission electron microscopes by the methods of total dissection, resin embedding, sectioning. The division ways of free nuclei in rice endosperm differed, including mitosis, amitosis, and the way that the daughter nuclei from mitosis went into amitosis without interphase. The division velocity of free nuclei in endosperm of rice varied with the internucleus distance. The velocity was faster when these free nuclei were separated from each other than when they were closed. Proper high temperatures could enhance the proliferation and also shorten the division cycle of free nuclei in endosperm, To a certain extent, the nitrogen fertilizer applied at the booting stage and proper drought treatment could accelerate the division of free nuclei.

Key words: rice, endosperm, free nuclei, division way, influencing factor

摘要： 为了探讨水稻胚乳分裂的过程及其影响因素，采用整体解剖和树脂包埋切片等方法，用光学和电子显微镜观察了水稻胚乳游离核的分裂方式及细胞学特征。水稻胚乳游离核的分裂具有多样性，既有有丝分裂，也有无丝分裂，还有有丝分裂后的子核不经间期随即进行无丝分裂等方式；游离核的分裂速率因核间距不同而异，核间距大时分裂速率比核间距小时快；气温升高能促进游离核分裂，缩短分裂周期；孕穗期施氮肥、适度干旱处理，都能在一定程度上促进游离核的分裂。

关键词: 水稻, 胚乳, 游离核, 分裂方式, 影响因素