Abstract: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.