胡杨小孢子发生及微管骨架变化与异常研究

Organization of Microtubule and Its Abnormities during Microsporogenesis in Populus euphratica

利用压片法和间接免疫荧光结合DAPI(4′,6-diamidino-2-phenylindole)染色法,对胡杨小孢子母细胞减数分裂过程中微管骨架变化和染色体行为进行观察研究。结果表明:(1)胡杨小胞子母细胞减数分裂进程中染色体行为正常,其中:偶线期可观察到单价体,中期Ⅰ会出现落后染色体,末期Ⅰ和末期Ⅱ的核仁呈现动态变化。(2)胡杨小孢子发生过程中细胞内微管骨架呈动态变化过程,其中:中期Ⅱ形成平行纺锤体以及三极纺锤体;末期Ⅱ未观察到典型的成膜体结构,同时型胞质分裂受子核间辐射微管系统调节,通过胞质向心收缩而发生,胞质分裂后形成四边形和四面体型四分体。(3)胡杨小孢子母细胞减数分裂过程中还存在各种异常细胞学现象,其中:中期Ⅱ平行纺锤体发生融合;中期Ⅱ和后期Ⅱ孢母细胞两个纺锤体间的胞质会出现裂沟;四分体时期存在三分体和二分体,并产生天然2n花粉和连体花粉。

In search of a new method to illustrate the microsporogenesis, indirect immunofluorescence microscopy with DAPI （4r, 6-diamidino-2-phenylindole） staining was conducted to observe the microtubule cytoskeleton pattern and chromosomes behavior during microsporogenesis of Populus euphratica. The results showed that： （1）Meiotic chromosome behavior is normal during microsporogenesis,with univalent at diplotene and lagging chromosome at metaphase I and the varied number of nucleoli. （2）Microtubule cytoskeleton was involved in many key processes of microsporogenesis. Spindles of metaphase II were mutually parallel or tripolar. No typically phragmoplasts were observed at telophase II ,while simuhaneous-type cytokinesis show an inward-oriented infurrowing of the callosic parental wall to partition the meiotic cytoplasm,mediated by the radial microtubules systems. The tetrad was shaped in a tetrahedral or isobilateral pattern. （3）Abnormal meiosis were also observed during microsporogenesis, such as fused spindles at metaphase II ,asynchronous division of the second meiosis, furrow occurred between the mutually parallels at the second division,as well as triad and dyad were found together with tetrad at tetrad stage,which led to formation of natural 2n pollen and stuck pollen.