Sporogenesis,Gametogenesis in Zephyranthes candida and Their Systematic Significances Mitosis and Amitosis of Generative Cell Nuclei in Artificially Germinated Pollen Tubes in Zephyranthes candida(Lindl.)Herb. Effects of Exogenous Abscisic Acid,Nitric Oxide and Hydrogen Peroxide on Stomatal Movement in Petals and Leaves of Zephyranthes candida Fusion Experiments of Isolated Generative Cells in Several Angiosperm Species Mass Isolation and Purification of Generative Cells from Pollen Grains