Study On Embryology Of Syringa Reticular Var. Mandshurica

This paper studies embryo development of Syringa reticular var.mandshurica by means of paraffin wax.The main content of this observation is the megasporgenesis and microsporgenesis,the development of male and female gametophyte,the fertilization,and the development of embryo and endosperm as well.The main results are as follows:(1)Anther wall includes 4 layer,anther wall includes the epidermis,fibrous layer,middle layer and tapetum.Anther wall developing is dicotyledonous type and galandular tapetum.Middle layer and tapetum dispear gradually during the pollen development.When the anther wall is mature it only remains epidermis and fibrous layer.In the meiosis of microsporocyte,cytokinesis is simultaneous type.And microspore tetrads are tetrahedral or zygomorphic.Mature pollen are 2-celled.(2)The ovary is 2-loculus with 2 anatropous ovules in each.The ovule is unitegmic and tenuinucellate.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 embryo sac is polygonum type.The innermost layer of the integu-ment differentiates as an endothelium tapetum.(3)The fertilization is of premitosis type.A sperm and egg cell fusion formation of homozygous;Another sperm and polar nucleus fusion formation of a primary endosperm.(4)The development of embryo belongs to Solanad type.The fertilized egg usually underwent a rest period before embarking on its first division.After the club-shaped embryo,the globular embryo,the heart-shaped embryo,and the fish-torpedo embryo developed the mature embryo. And the division of primary endosperm nucleus took place before division of the zygote.The primary endosperm did not undergo the rest period,and immediately mitosised.Endosperm is nuclear type.(5)The microsporogenes and male gametophyte are earlier than the megasporogenes and female gametophyte.This paper enriches the biological data of Syringa reticular var.mandshurica.And offers some theoretical foundation for scientific culture and heredity breeding on plant reproductive biology.