Analysis on mechanism of polysomaty and its application for cellular breeding

利用流式细胞术分析了几种植物在不同组织、幼苗生长和不同光照条件下的多体状态。在威尔士洋葱和菠菜中，在种子胚中没有发现多体现象，而是在萌发过程中产生的。在黑暗条件下，白菜的多体发育水平明显高于光照条件。在芦笋组织培养中也观察到多体水平的变化。在含有NAA的培养基上，愈伤组织形成早期倍性水平升高，倍性水平高的外植体倾向于产生倍性水平高的愈伤组织。当ccs基因被引入矮牵牛这一非多体细胞物种时，没有观察到多体细胞诱导。在石竹（Dianthus acacularis）这种非多体细胞植物的细胞悬浮培养中，阐明了细胞的多倍体化与植株再生能力的丧失密切相关，可以直观地选择和维持植株再生能力强的细胞。综上所述，本研究通过阐明多体状态与多种内部和环境因素的关系，提出了控制组织培养倍性水平的重要细胞育种策略。

Flow cytometric analysis was carried out to clarify the polysomaty status of several plant species in different tissues, during the growth of seedling, and under different light conditions. In Welsh onion and spinach, polysomaty was not found in embryo of the seeds but induced during germination. In cabbage, polysomaty level increased under dark condition compared with light condition. Change in polysomaty level was also observed in tissue culture of asparagus. On medium containing NAA, ploidy level increased during the early stage of callus formation, and the explants with higher ploidy levels tended to produce the calli with higher ploidy levels. When ccs gene, which is expected to relate polysomaty, was introduced into petunia, which is a non-polysomatic species, no polysomaty induction was observed. In cell suspension culture of Dianthus acicularis, which is a non-polysomatic species, it was clarified that polyploidization of the cells was closely related to the loss of plant regeneration ability, and that it was possible to select visually and to maintain the cells with high plant regeneration ability.In conclusion, this study proposed important cellular breeding strategies for controlling ploidy level of the tissue cultures through clarifying the relationship between polysomaty status and several internal and environmental factors.