芜菁小孢子胚胎发生及其显微结构观察研究

Research on Microspore Embryogenesis and Microstructure Observation in Brassica rapa L.

以喀什芜菁为材料，利用显微镜技术，研究小孢子胚胎发生过程。试验结果表明，没有进行热激处理的小孢子主要是沿配子体途径发育，即从四分体，经由单核靠边期、双核期，发育成为成熟的花粉粒过程；33℃热激处理1-3d后，小孢子改变发育途径，沿孢子体途径发育。部分小孢子出现细胞膨大，发生第一次有丝分裂分裂，形成2-细胞，2个子细胞之一发生垂直于子细胞壁方向的分裂，形成“T”型3-细胞原胚然后沿多细胞原胚、胚柄球形胚、鱼雷形胚、心形胚最终发育成子叶型胚。但随培养天数增加，大多数膨大的细胞不能分裂或分裂后停止发育。

Optical microscopes were used to study feature of the microspore embryogenesis in Brassica rapa L.. The research took kashgar turnips as materials. The test results showed that without heat shock treatment, the microspore is mainly along the gameto- phyte development way, that is, from tetrad, through Uninucleate at periphery, Binucleate stage to develop into mature pollen grain ; after 33℃ heat treatment, the way of microspore embryogenesis was changed, along the sporophyte development way. Some cells swelled, following the first mitotic division took place, then was 2-cell formation, one of the two daughter cells divided in vertical direction forming the ＂T＂ type 3 - cell proembryo, and then along the multicellular proembryo, globular-shaped embryo with a attached suspensor, torpedo-shaped embryo, hearted-shaped embryo, eventually developed into cotyledon-shaped embryo. But with culturing days increased, most of the swollen cells cannot divide or stop developing.