Preliminary Study On Reproduction Biology Characteristic Of Gigas Typy Tetraploid Black Locust (Robinia Pseudoacacia L.)

Tetraploid Black Locust was a quadruploid trees pecies from which a large-leaved and fast growing Black Locust introduced from South Korea was manned induced, which has such many excellent characteristics as fast growing, large leave, robust seedlings, excellent resistance entironmental restoration and biomass production. Black locust is a multipurpose legume tree species in our country and one of the important silviculture harbingers in northern region of our country.Crossbreeding as a effective way to cultivate excellent trees variety has been extensively applied on major economic trees breeding. Embryo abortion and Low seed seting percentage of Tetraploid Black Locust is very serious, and the result through hybridization is too serious to gain hybrid plant, so its artificial breeding remains blank up to now. Therefore it is necessary to expound the abortive mechanism, and to fend the method of puting of abortion and rescuing young embryo.In this paper, deals with the development of megaspore & microspore genesis and the formation of female& male gametophytes in Tetraploid Robinia psendoacacia. The characteristic of cytological development period of it' s microspore and corresponding shape of flower bud and their interrelation were investigated. Therefore, this research aims at providing a theoretic basis for the culture and breeding, and in order to be applied to guide suitable data in it' s embryology and the vitro culture of floral organ. The results of embryology were as follow:In addition, The anther is 4-sporangiateand its anther wall formation conforms to the dicotyledonous basical type. And also the two middle layers are ephemeral. The tapetum, of which each cell always remains uninucleate, is the secretory type. The cytokinesis after meiotic division of PMCs is simulataneous. Most microspore arrangement in the tetrad is tetrahedral, a few is obilateral. After the generative cell becomes free in the cytoplasm of the vegetative cell, its wall disappears. Besides, The mature pollen grains are binuclear with 3 or 4 apertures. They are triporate with thick netlike exine sculpture on their surfaces.The archesporial Cells cut off primary parietal cells and sporogenous cells, of which only one cell is functional. The megasport mother cell gives rise to unequal dyad and the linear tetrad. The chalazal megaspore in line type or T-type tetrad is functional. The development of embryo nary sac is of the polygonum type. The nuclear membranes of two polar nuclei fuse each other or don't before fertilization.. The mature ovules are campylotropous with dual-integrment and crassinucellate. Three...