小麦核仁在细胞周期中的变化

CHANGES OF THE NUCLEOLUS DURING CELL CYCLE IN TRITICUM AESTIVUM

运用Bernhard染色方法研究了小麦根端分生组织细胞核仁在细胞周期中的变化。结果显示 ,间期核仁染色很深 ,能够区分出纤维中心 (FC)、致密纤维组分 (DFC)和颗粒组分 (G) ,而染色质被漂白 ,在染色质间可以观察到细小的RNP颗粒。进入前期 ,在染色质的边缘有小的RNP颗粒分布。中期 ,染色体周边分布着类似于间期核仁的深染的大RNP颗粒 ,形成一个不完全连续的“鞘”状结构 ;在染色体内部看不到类似核仁的深染颗粒。到了后期时 ,仍可见RNP“鞘”状结构的存在。进入末期 ,这些RNP物质逐渐由“鞘”脱离 ,最后参与新核仁的形成。这些结果表明 ,核仁解体后的物质直接转移到了中期染色体的表面 ,并形成不连续的表层 。

The changes of the nucleolus during cell cycle in Triticum aestivum were studied by Bernhard staining method. It was observed that in interphase, the nucleolus was heavily stained. Fibrillar centers, dense fibrillar component, granular component could be identified in it. But the chromatin was bleached. The fine RNP granules were distributed at the interchromatin. During prophase, the small RNP granules appeared at the periphery of chromosomes. The larger heavily-stained RNP granules accumulated at the periphery of the metaphase chromosomes and formed a discontinuous 'sheath'-like structure. They were not observed at the interior of the chromosomes. This 'sheath'-like structure was also observed at anaphase. In telophase, the nucleolar materials were progressively separated from the 'sheath' and participated in the formation of new nucleoli. The results showed that the nucleolar materials were transferred directly to the surface of the metaphase chromosomes and formed a discontinuous coat, but not incorporated into the interior of the chromosomes.