景天科植物三种无性苗的形态发生

植物无性苗的发生过程是自然界植物所其特有的一种对应于有性生殖的无性繁殖方式。这种无性繁殖是与其体内胚性细胞的活动联系在一起的，并且这些具有胚性特征的分生细胞和组织又与植物组织、器官的发生和新植物体的重建存在一定的联系。这种现象不能不说是植物细胞全能性在植物体内的一种体现。无性苗的形态发生起源于具有胚性状态的起始细胞，不同的起始细胞，不同的分化状态以及不同的激素或配比都会对植物的无性苗的发生、发育产生影响。我们以景天科植物三种不同的无性苗，落地生根（Bryophyllum pinnatum），燕子掌(Crassula portulacea），石莲花(Hylotelephium ewersii)为材料，应用低温电镜和免疫细胞化学以及分子生物学技术，对无性苗起始细胞的微结构，细胞周期水平，分子生物学特点以及对激素的响应等进行研究，以期对植物无性苗的发生机理，无性繁殖及其细胞全能性有更深刻的认识。

The occurrence of plant clonal seedlings is a way of asexual reproduction corresponding to sexual reproduction in the nature. This process of asexual reproduction are linked to their activities of embryonic cells in vivo. And there is a link for the embryo characteristics of meristematic cells and tissues with the occurrence of the plant tissue, organ and new plants reconstruction. This phenomenon can not be said that is not a reflection of totipotency of plant cells in vivo. The asexual seedlings morphogenesis originated in the initiating cells with embryogenic state. It will affect the occurrence and development of asexual seedlings with different initiating cells, with various differentiation state and with the different hormones or their ratio. Three kinds of different asexual seedlings of Bryophyllum pinnatum, Crassula portulacea and Hylotelephium ewersii as materials are studied on the micro-structure of initiating cells in cloned seedling, the level of the cell cycle, molecular biological characteristics as well as a response to the hormone, by the application of cryo-electron microscopy, immune-cellchemistry and molecular biology techniques for better understanding of mechanism of clonal seedlings occurrence, plants asexual reproduction and the totipotency of plant cells.