[Ultracytochemical localization of calcium and ATPase activity on the 2,4-D induced somatic embryogenesis of Lycium barbarum L].

In order to research the function mechanism of the 2,4-D during the development of plant somatic embryogenesis, we studied its function mechanism and relationship with the space-time distributing of Ca2+ content and ATPase activity on somatic embryogenesis of Lycium barbarum L. The possible effects on 2,4-dichlorophenoxyacetic acid (2,4-D) induced somatic embryogenesis and changes of Ca2+ and ATPase active at different development period of somatic embryogenesis. The result showed: The 2,4-D was a key hormone for induced embryonic state of Lycium barbarum L. The embryonic callus and non-embryonic callus was separately obtained in the medium that contains the auxin 2,4-D and lack 2,4-D. In the present study, we have observed the Ca2+ was more abundant in the further intercellular matrix and on the cell wall at the multi-cellular stage, and Ca2+ was concentrated in the plasma membrane and vacuoles membrane during embryonic cell differentiate and division, to the globular embryo, more Ca2+ was seen in the nucleus. Afterward, it was also observed to be distributed in the thicken cell wall and intercellular matrix. At the same process, the variations of ATPase activity and Ca2+ were highly similar, ATPase activity was mainly located on the plasma membrane in early embryogenic cells. With further development, it was also observed to be distributed in endoplasm, nucleus and vacuoles, with the thickening of embryogenic cell wall, ATPase activity was found in the thickened region and the intercellular space. However, the variations of ATPase activity and Ca2+ have not clearly observed variety dynamics at the nonembryogenic callus, and with further vacuolation of nonembryogenic cell, Ca2+ content and ATPase activity gradually drop. It was indicated there was a closely relationship between the dynamics of Ca2+ and ATPase activity in somatic embryogenesis by 2,4-D induced. And the space-time distribution of Ca2+ and ATPase activity play a key role on signal transmission and the regulation of relevant gene expression.