植物体细胞胚发生中ATP酶活性时空分布动态与内源激素的变化

本文以我们的研究结果为基础，并结合国内外近几年有关研究报道，对植物体细胞胚发生中的超微结构和ATP酶活性时空分布动态及内源激素的变化和作用进行专题评述。⑴ 超微结构的变化：当植物体细胞一旦转化为胚性细胞后，各种细胞器相继增加，不仅丰富而且活跃，特别是线粒体内嵴发达，有的正处于分裂状态；核糖体聚集成多聚核糖体；质体中含大量淀粉粒，接着出现高尔基体等。早期胚性细胞与周围细胞还存在胞间连丝，随着胚性细胞壁的加厚，胞间连丝也随之消失。⑵ ATP酶时空分布动态：早期的胚性细胞中ATP酶反应产物主要沉积于质膜和液泡膜上，后期ATP酶活性转入细胞内，液泡和细胞核中，而且在胚性细胞壁加厚处有活跃的ATP酶活性反应，并证明ATP酶活性是在胚性细胞发生过程中形成的。⑶ 内源激素的变化与作用：在体细胞胚诱导过程中内源激素起着关键性作用，内源生长素含量的提高为胚性细胞的诱导奠定了基础，细胞分裂素含量的增加可促进胚性细胞的分裂和增殖，ABA不仅提高了体细胞胚的诱导频率，而且促进了体细胞胚的正常发育。

ATPase Activity and Endogenous Hormone Changes during Plant Somatic Embryogenesis

This article reviews recent progresses in research on plant somatic embryogenesis based on our experiments and research reports by others. (1) Changes in ultrastructure: Once a plant somatic cell turns into embryonic state, the number of organelles increases significantly, with mitochondrial crista much developed an d some of them in the dividing state. Ribosomes assemble into polyribosomes; plasmids contain a great deal of starch granules; the emergence of Goligi apparatuses then follows. Between the embryonic initial cell and surrounding cells, there exist plasmodesmata that will disappear when the embryonic cell wall growing thick. (2) ATPase ultracellular chemical location: In the initial embryonic cell, ATPase reaction products are mainly deposited on plasma membranes and vacuole membranes. In the later stage, ATPase activities come into the cell, vacuoles and nucleus. In addition, ATPase activity reaction are active in the thickened embryonic cell wall. We could draw a conclusion that ATPase activity gradually forms during plant embryogenesis. (3) Endogenous hormone change and function: Endogenous hormones are critical factors in inducing the formation of somatic embryo cells. The rise in endogenous auxin level is the base for the induction of embryonic cells. The rise of cytokinin level can promote cell division and proliferation. ABA not only increases somatic embryo induction ratio, but also promotes its normal development.