Female Gametogenesis And Polyploidy Induction Of Populus Adenlpoda Mazim

Populus adenlpodn Mazim,which grows natively in the south of China,is a kind of tree species for timber specially.The tree was a secondary wilderness species and there was a little research on its genetic improvement.In order to meet the increasing requirement of wood production in southern mountain of China,it was necessary to make a genetic improvement program on Populus adenlpodn.In this paper,the meiosis of megaspore mother cells(MMCs),embryo sac development,chromosome doubling and triploid introduction of Populus adenlpodn were studied.All results as following:The meiosis started after 110hs when the flower branches of Populus adenlpodn were cultured in water and it would took 5ds for the megaspore mother cells developed into mature pollens;The meiosis of MMCs appeared to a major association to the external morphology of female inflorescence.There were asynchronous meiosis in different clones,inflorescence,culture condition and the location of the tree.The asynchronous meiosis maybe a kind of mechanism to adapt to rainy environment when they were pollinated.The embryo sac of Populus adenlpodn Mazim is a Polygonum type.The embryo sac developed during 18h to 42h after pollinated.Furthermore,An egg cell fused with one of the sperms and developed into a zygote at 48hs after pollination.Different weather and soil-condition made the stage of embryo sac diversity which was in respct that diffent gene.Although collected from different years and locations,clones of Populus adenlpodn Mazim water-cultured in the same time after pollination were basically in the same period of embryo sac developmentThe technology of triploid induction through direct treating of female inflorescences with colchicines was established.461seedlings were obtained by controlled cross,but there were no triploid found.Which maybe attribute to the low accuracy of pollination time and treatment time,the asynchrony of female gametogensis.