沙打旺组织培养中脱分化细胞的超微结构及细胞核的动态变化

对沙打旺的下胚轴、子叶、幼叶组织培养中脱分化细胞进行了超微结构观察，并着重讨论了细胞核的动态变化。脱分化细胞的细胞质中线粒体墙加，嵴明显；多聚核糖体增多；高尔基体增加；质体中积累淀粉。核仁与核内异染色质之间有一个动态过程。此过程暂称“核仁物质喷射“现象。在致有以下：１．核体出现，半嵌在增大的核仁上，核内异染色质沿核膜凝聚；２．异染色质移向核仁，并与核仁接触，核体消失，部分异质进入核仁；３．核仁物质

THE ULTRASTRUCTURE AND UNCLEUS DEVELOPMENT OF DEDIFFERENTIATING CELL IN TISSUE CULTURE OF ASTRAGALUS HUANGHEENSIS

The ultrastructure and nucleus development of dedifferentiating cell in tissue culture of hypocotyl cotyledon leave in Astragalushuangeensis are observed and analysed,Mitochondria, golgi and polyribosomes increase in dedifferentiating cell,There is accumulating starch in plastid.A developmental process between nucleolus and heterochromatin is observed in dedifferentiating cell.This process is called as "nucleolus matter sprey" phenomenon temporaryly,It can be divided into a few stages:1.Nucleolusenglarges and heterchromatin condenses near the nuclear membrance. NOR.(nucleolar organizer regions)appear evidently a:spherical bodies in direct contact with the nucleolus.2.The heterchromatin move to the nucleolus and get in contact with the nucleolus. The nucleloar organizer regions disappear. Part of heterchromatin enter the nucleolus.3.The substance in nucleolus mix with heterchromatin entering into nucleolus,then the mixture is sprayed in form of band and pearl.The process occurs before the earlier mitosis prophase. It seems to be considered as mark of dedifferentiating cell.