甜菊花粉发育的超微结构及细胞化学

以电镜观察甜菊花粉及发育的结果表明:小孢子母细胞时期,出现胞质融合以及线粒体和质体数量减少、结构简化的胞质重组现象。四分孢子的显著特征是细胞核和高尔基体呈活跃状态。花粉双核期,营养细胞内出现大量的淀粉粒和脂质体,细胞器丰富,核孔多,而生殖细胞胞质稀薄核孔较少见。本文中探讨了这二类细胞的功能。双核期花粉内淀粉粒和蛋白质开始大量积累。三核期花粉成熟时,蛋白质积累达高峰,淀粉粒转化为较小分子的糖类物质以供花粉萌发生长。

UltrastTucture and Cytochemistry Studies on the Pollen Development of Stevia rebaudiana Bertoni

In the period of microspote mother cell, there was the phenomenon of cytomixis: The numbers of the mitochondria and the plastids decreased, and their structure simplified. The characteristics of tetrad was that the nucleus and Golgi bodies being in the active state. When pollen was in the two-cell period, a great number of starch grains and lipid bodies appeared in the vegetative cell which had abundant organelles and nuclear pores; but less cytoplasmic component and a fewer nuclear pores existed in the generative cell. There were more RNA and acidic protein in the vegetative nucleus than in the generative nucleus. These data indicate that there are probably material exchanges between the two cells. The vegetative cell provides nutrients for the generative cell. The pollen in two-cell stage begin accumulating larger amount of starch and protein. In the process of pollen maturation, protein becomes more abundant and starch grains are being transformed to small molecules of carbohydrate supplying the germination of the pollen.