Megasporogensis,Microsporogenesis and Development of Male and Female Gametophytes of Endangered Berchemiella wilsonii
To explore whether there were any endangered links in sporogenesis and development of male and female gametophyte of endangered Berchemiella wilsonii,the reproductive biology of B.wilsonii was observed using paraffin section technique.The results showed that the flower of B.wilsonii had five stamens,four anthers,and the mature anther wall was composed of one inner layer,two middle layers and one tapetal layer.The tapetum developed normally with regularly arranged cells closely connected with the middle layer cells containing multiple nuclei in each cell.The cytoplasmic division of microspore mother cells was synchronous during meiosis,and mainly formed tetrahedral tetrads,the mature pollen grains were bicellular,round or oval in shape,which most of them had three germinating tubes.There were a few abnormal tapetum development and a few abortive pollen during anther development.B.wilsonii had two locule in ovary,only one chamber developed.The ovule was anatropous double integuments and crassinucellate.The chalazal end megaspore developed into functional megaspores,which underwent three times consecutive mitosis and further developed into polygonum embryo sac with seven cells and eight nucleus.Ovary ovule development was basically synchronized.The process of the mega-microsporogenesis and development of female and male gametophyte of B.wilsonii were normal,which was not the reason for the low seed setting rate.
Berchemiella wilsoniiembryologymacrosporogenesismale and female gametophyte development