Study On Embryology Of Celastrus Orbiculatus Thunb.

In this paper,embryo development was observed by paraffin wax section in Celastrus orbiculatus Thunb..Include megasporgenesis,microsporgenesis,the development of male and female gametophyte,and the development of embryo and endosperm.(1)Anther wall includes 4 layer,anther wall includes the epidermis,fibrous layer,middle layer and tapetum.Anther wall developing is basical type and galandular tapetum.Middle layer and tapetum dispear gradually during the pollen development.When the anther wall is mature it only retains epidermis and fibrous layer.The cytokinesis after meiotic division of PMCs is simultaneous and the microspore arrangement in the tetrad is tetrahedral.Later,monocyte microspore are separated to 4 single-cell.After the growth of the microspore,the nuclear begin divide.Mature pollen is 2-cells type.(2)Under the scanning electromic microscopes.The pollen grains of Celastrus orbiculatus Thunb.is generally long globose,equator positiong enlargement,with three germination groove, and the groove at both ends as long as.The Patterns are reticulate.The mesh size is different at each other.The mesh size is small in the near of germination ditch.(3)The ovary is 2-loculus with 2 anatropous ovules in each,bitegmic and crassinucellate.Usually one archesporium functions directly as megadpore mother cell.Cytokinesis in the megaspore mother cell usually accompanies meiosis,and the chalazal megaspore of a linear tetrad is functional one.The innermost layer of the integu-ment differentiates as an endothelium tapetum.The embryo sac is polygonum type.(4)A sperm and egg cell fusion formation of homozygous;Another sperm and polar nucleus fusion formation of a primary endosperm.The fertilization is of premitosis type.(5) Endosperm is cellular type.Primary endosperm nucleus divides as soon as it formed, hundreds of free endosperm nuclei occurs when zygote begins to divid.(6) The female gametophyte is later than male gametophyte.The female inflorescence is begin to growth when the male inflorescence is development to monocyte microspore.When the female inflorescence is in between double nucleus embryo sac and mature embryo sac,the stamen is spread pollen.The mature embryo sac is growth after spread pollen 4～6 days.