F型小麦雄性不育系小孢子发育的细胞学观察

Cytological Observation on Meiosis and Development of Microspores in F-type Male Sterile Wheat Line

为明确F型小麦雄性不育系雄性败育的细胞学机理,以西农979为对照,采用醋酸洋红染色制片等方法观察花粉母细胞减数分裂、小孢子发育过程及成熟花粉粒育性表现,并套袋自交,于成熟期统计结实率。结果发现,F型小麦雄性不育系仅有2.15%的花粉母细胞减数分裂Ⅱ异常,其余绝大多数花粉母细胞减数分裂正常,但小孢子由单核期进入二核期后,生殖核和营养核先后降解,导致无核小孢子的出现,其比率为77.04%。成熟花粉粒经1%I2-KI染色后显示异常的花粉粒比率高达94.8%,其中包括圆败、典败和染败类型,但以染败型为主。F型小麦雄性不育系套袋自交结实率为2.5%。上述三方面的研究结果彼此相符,据此认为,小孢子由单核期进入二核期后,生殖核和营养核先后降解导致无核小孢子的产生是F型小麦雄性不育系雄性败育的主要细胞学原因。

To clarify the cytological mechanism of pollen abortion in F-type male sterile wheat line,the normal wheat variety Xinong 979 was taken as control.The meiosis of pollen mother cells and the development process of microspores were observed after acetate carmine dyeing.The results showed that only 2.15%of the pollen mother cells divided abnormally in meiosisⅡ and the others underwent meiosis normally.The nucleus of microspores underwent mitosis after mononuclear stage,producing agenerative nucleus and a vegetative nucleus.However,the generative nucleus degenerated at first and then the vegetative nucleus degenerated,resulting in empty microspores.The empty microspores accounted for 77.04% of total microspores.The mature pollen grains were checked after dyed by 1%I2-KI,94.8% pollen grains were abnormal judged by their shape and the degree of dyeing.The self-seed set ratio of F-type male sterile wheat line was 2.5%.The above results were matched.Accordingly,we concluded that the degeneration of nuclei after mononuclear stage was the key factor resulting in pollen abortion in F-type male sterile wheat line.