In Vitro Divisions of Unfertilized Central Cells and Other Embryo Sac Cells in Nicotiana tabacum var macrophylla Ultrastructural Observations on Parthenogenesis and Antipodal Apogamy of Allium tuberosum Roxb The Structural Changes During the Degeneration Process of Antipodal Complex and Its Function to Endosperm Formation in Wheat Caryopsis POLYEMBRYOGENESIS IN APOMIXISPARENT Ⅳ OF RICE Transport of Disassembled Protoplasm from Degenerated Nucellus into Embryo Sac and Its Role in Feeding the Proliferating Antipodals in Wheat EMBRYO SAC DEVELOPMENT AND EMBRYOGENY IN ALLIUM TUBEROSUM