关键词: 西畴含笑, 大小孢子发生, 配子体发育, 败育, 极度濒危

Abstract: The mega- and microsporogenesis and development of male and female gametophytes of Michelia coriacea were investigated using paraffin section method . The anther of the species was tetrasporangiate and its anther wall was composed of 5 - 7 layers cells, and the tapetum belonged to glandular type. In the meiosis of microsporocyte, cytokinesis was modified simultaneous type. The tetrads were tetrahedral, decussate and sometimes were anomalous type. Mature pollen grain was twocelled. The ovule was anatropous, bitegmic, and crassinucellar. The megaspore mother cell undergone meiotic divisions and developed into a linear type of tetrads. The chalazal megaspore of the tetrad was functional. The functional megaspore underwent three successively nuclear divisions to give rise to eight-nucleate embryo sac which was Polygonum Type. The high percentage of abortion could be observed in process of megaspore and microspore genesis and the development of gemetophytes. The abnormality in the reproductive development of this species might be the main cause of its extremely low seed set .

Key words: Michelia coriacea