毛白杨花粉母细胞减数分裂及其进程的研究

采用细胞遗传学方法对毛白杨 (PopulustomentosaCarr.)花粉母细胞减数分裂及其进程进行了研究 .结果表明 :①毛白杨花粉母细胞减数分裂进程有一定的规律 ,且与花序的形态和花药颜色变化有密切相关 ;②减数分裂染色体行为表现因个体不同而不同 ,终变期、中期Ⅰ有数目不等的单价体出现 ,在后期Ⅰ乃至末期Ⅰ、末期Ⅱ可见到单独存在的落后染色体 ,体现了毛白杨遗传上的异质性 ;③毛白杨减数分裂存在多核仁现象 ,在末期Ⅰ、末期Ⅱ最多可见到含 8个小核仁的子核 ,并且随着减数分裂进行 ,多个小核仁发生合并 ,最终生成一个大核仁 ;④毛白杨各无性系在减数分裂进程上存在着差异 ,甚至同一雄性无性系植株的不同花芽或同一花芽上不同部位等 ,其花粉母细胞减数分裂时期也表现为不同步性 ,显示了种群变异的多样性和丰富性

Meiosis and its stages of pollen mother cells in Chinese white poplar

The meiosis and its stages of pollen mother cells(PMC) of Chinese white poplar( Populus tomentosa Carr.)were studied by the methods of cell genetics in this paper. The results suggested: ① Certain regularity existed in the stages of meiosis of PMC, and the stages were closely correlated with the morphology of inflorescences and the variation of anthers color. ② The behavior of chromosomes during meiosis was different among clones. Univalents in different quantities were found at diakiness and metaphase I, and the separated lagging chromosomes at anaphase I and even at telophases I and II, which indicated the genetic heterogeneity of Chinese white poplar. ③ The occurrence of the multi nucleoli was observed in the stages of meiosis of PMC, with daughter nucleolus containing 8 nucleoli at telophases I and II which merged into one large nucleolus with the development of meiosis. ④ The difference in stages of meiosis existed among Chinese white poplar clones, and even different floral buds in one male tree or different positions in one floral bud showed non synchronization in the meiosis periods of PMC. This suggested extensive population variation in Chinese white poplar.