STUDIES ON SOMATIC EMBRYOGENESIS FROM CELL SUSPENSIONCULTURE OF LOBLOLLY PINE Abnormal Behavior of Nuclei and Microtubule (MT) Organizational Changes During Embryo Sac Development in the Poly-Egg Mutant, APⅣ of Rice Cytoembryological Studies on Polyembryonic Line SB-1 of Oryza sativa: Polyembryong and Its Origin Formation and Development of Different Types of Embryo Sacs in Polyembryonic Rice Strain APⅣ Polyembryony and Multiple Seedlings in the Apomictic Plants Study on the Structure and Genetic Polymorphism of Embryo Sac in Polyembryonic Rice Strain AP Ⅳ Embryological Observation on the Apomictic Rice-ApⅢ (Shuang 13) Fertilization of Different Types of Embryo Sacs and Its Embryo Formation in Polyembryonic Rice Strain APⅣ