外壁破裂对油菜小孢子胚胎发生影响的显微观察

Ultrasturctural Studies on Broken Exine Roles for Microspore Embryogenesis in Brassica napus L.cv. Topas

摘要: 前期研究表明，油菜裂外壁小孢子也能胚胎发生。本研究以油菜裂外壁小孢子为材料，利用超微结构显微观察了破裂的外壁对胚胎发生的影响。结果表明，裂外壁小孢子可表现出与合子相似的某些结构特征；与合子进行不均等分裂而形成形态、结构迥异的顶基细胞类似，裂外壁小孢子也可以进行不均等分裂，形成大小和结构不同的两个子细胞。这些结果暗示破裂的外壁在小孢子极性生长和启动胚胎发生过程中重要作用。

Abstract: In prior studies, the exine-dehisced microspore could also embryogenesis. Early events in micro-spore embryogenesis, such as polarity establishment, cell wall development, and the first division plane decision were investigated to reveal the mechanism controlling the process. In this paper, ra-peseed exine-dehisced microspores were used to reveal the roles of exine for microspore embryo-genesis by ultrastructural observation. The results show that some ultrastructural characteristic of the microspore is comparable to that of zygote, and that the dividing behavior of some exine-de- hisced microspore is similar to that of zygotes which could divide asymmetrically, resulting in two different daughter cells. This observation suggested that broken exine may play an important role in the polarity establishment during microspore embryogenesis.