Abstract:
Akebia trifoliatabelongs to Akebia of the Lardizabalaceae family,and it is a dioecious,monoecious woody vine,with economic value for medicine and food. In order to understand the sexual reproduction process of A. trifoliate,analyze the reproductive reasons of the low seed setting rate of this species under natural conditions,and provide a theoretical basis for its hybrid breeding and new variety cultivation,the embryological characteristics of mega-and microsporogenesis and female and male gametophyte development of A. trifoliate were observed by paraffin section technology. The main results showed that A. trifoliata had six stamens with four locules in each,and the anther wall was fully differentiated,and it was composed of epidermis(1 layer),endothecium(1 layer),middle layers(2-3 layer)and tapetum(1 layer)from outside to inside,tapetum belonged to glandular type respectively. The cytokinesis of the microspore mother cell in meiosis was of simultaneous type,and the tetrads were arranged in a tetredraltah,mature pollen grain was two-celled. There were little pollen abortion,and abortion occurred at the microspore tetrad stage. The ovary was one locular,parietal placentation,ovules were hemianatropous,bitegminous and crassinucellate. Its megaspore was of monosporogenesis type,and tetrads were linearly arranged. 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,another three megaspores degenerated. The early development of the stamens in the female flowers was normal,but the microspores did not develop further until the uninucleate pollen grain stage,the tapetum was not completely degraded,and the anther wall did not crack,the degeneration of the carpel of the male flowers was due to the early lack of development,the carpels heal incompletely,and no ovules are produced. The process of the mega-microsporogenesis and development of female and male gametophyte of A. trifoliata were normal,which was not the reason for the low seed setting rate,but may be related to external factors affecting pollination.