Abstract:Using slicing and total dissection techniques, we observed the process of division and proliferation of free nuclei, and endosperm cellularization in Ginkgo biloba L. We analyzed the proliferate development of endosperm cells by the means of disassembling endosperm with the cellulose enzymes. The results showed that the division and proliferation of free nuclei occurred 5-30 days after pollination and cellularization occurred about 30-65 days after pollination.The female gametophyte mitosis resulted in many free nuclei, which was spherical shape with the average diameter of 2-4 μm. At the initial stages, the free nuclei distributed in the central cytoplasm. However, with the volume of central vacuoles increasing, cytoplasm and nuclei were pushed to around. Then, one layer of opening cells that had no cell wall at the side near central vacuole formed in the periphery after the formation of about 4 000-5 000 nuclei. Cells around grew centripetal and dissociative, till cavum was filled with endosperm cells and the cellularization was finished. The proliferate development of the endosperm cells took on “S”-shape curve, which was slowly at the early stage after pollination, then it changed faster during 40-55 days after pollination, and the number of endosperm cells reached the maximum at 65 days after pollination. Afterwards, the number of endosperm cells did not significantly changed. Therefore, the division and proliferation of free nuclei have unique traits, and the number of endosperm cells play a significantly role in the development of seeds in G.biloba.