【摘要】 通过对正常粒和败育粒胚胎发育的形态解剖观察,明确了凡是能抽出花丝的各部位小花,在授粉前基本上均可发育成完整的成熟胚囊,仅在胚囊大小上有所差别。 授粉后不同位势间胚乳和胚的分化发育存有一定差异,开始表现在时间早晚、数量多少、形态及大小不同等方面,最终导致劣势位粒(穗顶部)的败育。发生粒败育的重要原因是在发育过程中籽粒间的营养竞争和物质分配不均衡、穗顶部籽粒缺乏足够的养分所致。 籽粒败育首先是胚乳发生败育,使胚的分化发育失去了物质供应来源,胚的分化发育受阻。籽粒败育的决定时期以胚乳败育为转折点,早者在授粉后8-12天,晚者在授粉后16-21天。更多还原

【Abstract】 The morphology and anatomy of abortion grains at the ear top of maize were studied. The results showed that all pistill ate florets diked before pollination at the ear top could develop with complete and maturity embryo sacs, similar to those of the middle and lower florets, although they were smaller than the latters. After pollination, however, their endosperms and embryoes developed and differentiated differently with the normal ones in beginning later and stopping earlier, less endosperm cells, starch grains and embryonic primordiums and smaller embryoes. The main cause of abortion was their poor competition abilities for nutrients with normal grains and lower proportion of substance distribution in them. The results indicated that endosperm abortion took place earlier than embryoes. Therefore, embryo development was prevented for without source of matter supply. The key period of grain abortion was just the beginning of endosperm abortion, 8-12 days and 16-21 days after pollination for the earlier and later abortion grains respectively.更多还原