Mechanisms of plant somatic embryogenesis

Based on our experimental results and the related research reports, this review addresses some important issues about plant somatic embryogenesis. Once plant somatic cells develop into embryonic cells, the organelles of the cells increase, and their function is active. In the early stage of embryogenic cells, the reaction products of AT-Pase are mainly deposited on the plasma and vacuole's membranes, then the activity of ATPase can be found in the cytoplasm, vacuole and nucleus in the late stage of embryogenic cells. ATPase-catalyzed reaction occurs actively in the thickened wall of embryogenic cells. Endogenous hormone is a critical factor affecting somatic embryogenesis. Superox-ide dismutase (SOD) activity, which is closely related to embryogenic cell differentiation, is much higher in differentiated embryogenic cells than in undifferentiated cells, indicating that embryogenic cells have stronger function of antioxida-tion. In addition, the lower level H2O2 can promote embryogenic cell differentiation. The programmed cell death (PCD) exists in the process of embryogenic cell differentiation and development, and the active oxygen species plays an important role in inducing of plant PCD.