Flower bud differentiation and development of male and female gametophytes in Camellia oleifera

Abstract

Cytological observation on the development of female and male cells of Camellia oleifera 'Xianglin No.1' was carried out by the method of paraffin sectioning,and the correlation between flower bud differentiation and its external morphology was analyzed.The results show that:(1) The development of flower bud differentiation could be divided into 6 stages: pre-differentiation,sepal formation,petal formation,stamen and pistil formation,ovary and anther formation,and stamen and pistil maturation;(2) 'XL No.1' had four ventricles in each anther;the development of the anther wall belonged to the basic type;glandular tapetum;the meiosis in the microspore mother cells belonged to the simultaneous type and the microspores were arranged in a tetrahedron shape in the tetrads;pollen matured in seven to nine days before blooming;The ripened pollen was of 2-cell type;(3) The ovule was anatropous ovule,nucellus thin,with a double integument;the megasporocyte underwent meiotic division,giving rise to two dyad cells,only the megaspore at chalazal end had biological function,forming 7 nuclear and 8 embryo sacs that underwent 3 mitosis as the onion-type embryo sac.(4) During the process of development,not only the formation of androecium and gynoecium had stable corresponding relations,but aslo they all corresponded with the external morphology.According to the corresponding relations in time sequence,the development process of the interior sexual cell could be identified by the external morphology.