关键词: 巴东木莲, 大孢子发生, 小孢子发生, 雌雄配子体发育

Abstract: A detailed morphological description of megasporogenesis, microsporogenesis, and development of the male and female gametophytes in the rare endangered plant Manglietia patungensis Hu is presented for the first time after three-year’s continuous investigation. The ovule is anatropous, bitegmic, crassinucellate and with a obturator. No irregularities have been found in the process from the differentiation of archesporial cells to the formation of megaspores. The megaspore mother cells undergo miosis and develop into a linear tetrad. The large one at chalazal end is functional megaspore and developed into a polygonum type of embryo sac after the third mitotic division. Each anther of M. patungensis Hu with four sacs, a mature anther wall successively comprises an epidermis, endothecium, two-layered middle layer and one or two-layered glandular tapetum. The meioses of microspore mother cell is normal and cytokinesis is modified simultaneous type, and tetrads are tetrahedral, decussate and isoblateral，occassionally linear. The pollen grains are monocolpate and two-celled at shedding and the pollen grains germination rate is more than 90%. These results indicate that the key factors for the low seeding rate do not involved the development process of male and female gametophytes.

Key words: Manglietia patungensis Hu, megasporogenesis, microsporogenesis, development of gametophytes