摘要
讨论了甘薯受精前后卵器各细胞超微结构的变化.助细胞在珠孔端具有丝状器,并有丰富的内质网、线粒体、高尔基体和质体(在宿存助细胞中特别丰富),花粉管进入到退化助细胞中并将内含物释放出来.卵细胞具有丰富的线粒体、内质网和核糖体.受精后,类脂体、高尔基体、线粒体和核糖核蛋白体明显增加.受精前卵器各细胞只有珠孔端具有壁,受精后合子的高尔基体的数量和活性增加.还比较了甘薯卵器和到目前为止研究过的其它一些植物卵器超微结构的异同.
The changes of the ultrastructure on the cells of the egg apparatus befors and after fertilization in the sweet potato and the function of synergids are chiefly discussed in this paper. A prominent ferture of the synergids is the filiform apparatus at the micropylar end of each cell different from the other cells in the embryo sac. The features of synergids before fertilization are, on the basis of ultrastructure, numerous endoplasmic reticulum and mitochondria. In addition, they have dictyosomes and plastids (containig starch grains). This shows that synergids are healthy, intact, functional cells. This is related to secretion of chemotropic substances that function in guiding the growth of the pollen tube. The cell wall of synergids only extends a short distance around the micropylar end of the cells. Just before fertilization, one of the synergids degenerates . This is the synergid that receives the pollen tube and its discharge, incluiding both male gametes. The other (persistent synergid) degenerates slowly after fertilization. It has abundant starch grains. This explains synergid is related to the absorption, traslopcation and storage of metabolites. Besides, dictyosomes increase in number and activity after fertilization. No plasmodesmata are present in these cells. There are numerous mitochondria, endoplasmic reticulum, ribosomes, dictyosomes and lipid bodies in the egg cell. A cell wall is present only around the micropylar end of egg. After fertilization, a little changes occur in the zygote. The zygote is approximately the same as the egg. The number and activity of the dictyosomes increase, apparently in relation with the cell wall formation and cell mitosis. The number of lipid bodies and ribosomes increases. Comparisions are made between the egg apparatus of the sweet potato and that of other plants studied till present.
出处
《西南师范大学学报（自然科学版）》
CAS
CSCD
1991年第3期362-367,共6页
Journal of Southwest China Normal University(Natural Science Edition)
关键词
甘薯
受精
卵器
超微结构
sweet potato (Ipomeoa batatas)
egg apparatus
ultrastructure
fertilization
