XVI International Botanical Congess
During double fertilization one of the two sperm cells fuse with the egg to generate an embryo, while the other one fuses with the central cell to develop into the endosperm. In maize, these two processes are now possible to be performed in vitro. Fusion of a single central cell with a single sperm cell results in development of endosperm in culture. Fusion of sperm nuclei occurred either with one of the two polar nuclei or with the secondary nucleus within 2 h after in vitro cell fusion. The transition from the syncytium to the stage of cellularization was observed 3 - 5 days after in vitro fertilization. Cell division occurred highly synchronized and at a high frequency. Similarly to the early embryo, in vitro endosperm developed into a highly polarized structure.