Study On Embryology Of Juglans Mandshurica Maxim

In this paper,embryo development was observed by paraffin wax section in Juglans mandshurica Maxim..Include megasporgenesis,microsporgenesis,the development of male and female gametophyte,and the development of embryo and endosperm.Juglans mandshurica Maxim.is dichogamy,and divides into female first and male first.Anther wall includes 4 layers,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,terads are separated to 4 single-cell.After the growth of the microspore,the nuclear begin divide.Mature pollen is 2-cells type.The ovary is 1-loculus,atropous and unitegmic,crassinuceUar.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 or T-shape tetrad is functional one.The embryo sac is polygonum type.The innermost layer of the integu-ment differentiates as an endothelium tapetum.The first division of zygote is transversally occasionally.The embryo development goes through the following stages:the global proembryo,the pear-shape embryo,the heart-shape embryo,torpedo embryo,mature embryo.Endosperm is nuclear type.Primary endosperm nucleus divides as soon as it formed,hundreds of free endosperm nuclei occurs when zygote begins to divid.We analyzed the relationship not only between the development of anther and outside development of male flower,between the development of ovule and the outside development of male flower but also the development of ovule and the development of anther.Anormogenesises were observed in certain stages of development.This paper enriches the biological data of Juglans mandshurica Maxim.And offers theoretical foundation for scientific culture and heredity breeding on plant reproductive biology.