白菜的内多倍化现象

研究和了解植物内多倍化现象的发生规律和特点对于有效调控器官分化过程, 加速有用器官形成具有重要意义。本文分别以白菜及其近缘属种为材料, 运用流式DNA分析技术, 系统检测了不同发育阶段、不同组织器官以及不同种属植物叶片的内多倍化水平。结果表明, 白菜的内多倍化特点同样具有组织、发育阶段和种属特异性。一些木质化程度较高的输导组织如幼根、胚轴、茎和叶柄比其他非输导组织的叶片、子叶、苞叶具有更高的内多倍化程度; 在给定的组织器官中内多倍化水平随该器官的发育进程而提高, 当器官成熟时, 内多倍化水平也趋于稳定; 显微观察结果表明, 不同倍性的细胞核大小差异悬殊, 呈无规律状态散布于白菜表皮组织相邻的细胞内; 最高倍性水平的细胞核, 在白菜叶片中为64C, 而在甘蓝、芥菜和拟南芥中分别为32C、16C、16C, 在同科的不同植物中显示了不同的内多倍化水平。

Endopolyploidization Phenomenon of Chinese Cabbage (Brassica rapa ssp.pekinensis)

The endopolyploidization is a universal phenomenon existing in the higher plant. The endopolyploidization, on which plant cells maintained a faster growth rate, is an important way of increasing copies of function genes which is necessary for plant to adapt its growing environment. The knowledge and research on the occurring and the feature of plant endopolyploidization phenomenon would be helpful for regulating efficiently differentiation of organs and accelerate the formation of valuable organs. In this paper, the Chinese cabbage and its relatives were used to determine the endopolyloidization level in tissues, organs, and leaves at different developmental stages with the technique of flow DNA analysis. The results showed that in Chinese cabbage the feature of endopolyploidization was also specific for tissues, developmental stages like in other plants reported previously. Some conducting tissues with higher lignification degree such as primary root, hypocotyls, stem and petiole demonstrated higher endo-polyploidization level than other nor-conducting tissues such as bract, cotyledon, laminae. In a given organ, the endopolyploidiza-tion level was raised in the progress of the organ development. When the organ was up to maturity its endopolypoidization level tended to be stable. The micros-graph revealed that the nuclei with different ploidies showed obvious difference in size and were scattered randomly into adjacent pellicle tissue cells of petiole of Chinese cabbage. The highest ploidy level of nuclei was 64C in leaves of Chinese cabbage, but 32C, 16C, and 16C in leaves of cabbage, mustard, and Arabidopsis thaliana, respectively, indicat-ing that the endopolyploidization level of the different plants in the same family is different.