响叶杨小孢子母细胞减数分裂及染色体行为的研究

Meiosis and Chromosome Behavior of Microsporocytes in Populus adenopoda Maxim

采用醋酸洋红压片法对响叶杨(Populus adenopoda)小孢子母细胞减数分裂进程中的染色体行为进行了研究。结果表明:响叶杨小孢子发生发育过程与其雄花芽/花序的外部特征和花药颜色有着密切关系;在其减数分裂进程中染色体行为正常,表明响叶杨同源染色体间表现出了较高的同源性,在中期Ⅱ平行纺锤体的出现与天然花粉中大花粉的存在可能有一定的联系;同时,减数分裂过程中核仁数目存在着动态变化,这种现象可能与杨属植物古多倍性起源有关。同一花芽的不同部位,减数分裂进程较不同步,这种不同步性是响叶杨适应环境的一种进化表现。

The meiosis and chromosome behavior of microsporocytes in Populus adenopoda were studied by aceto-carmine squash technique. The meiosis of the pollen mother cells of P. adenopoda showed a high correlation to external characters of male flower buds/inflorescences and anther color. The normal behavior of chromosome indicated a high degree of homology among the homologous chromosomes of P. adenopoda. However, the appearance of paralleled spindles at metaphase 11 may result in big pollen grains. The varied number of nucleoli during meiosis of microsporocytes was probably due to ancient polyploid origin of Populus. The differences in the processes of meiosis in P. adenopoda occurred not only in different buds, but also in different parts of the flower bud. This meiosis asynchronicity was an important character of evolution for environmental adaptation during sexual reproduction of the genus.