臭椿雄蕊的发育和雄配子体的形成

Development of Stamens and Formation of Male Gametophyte of Ailanthus altissima (Mill.) Swingle

利用常规石蜡制片技术，对臭椿[Ailanthus altissima（Mill．）Swingle]的小孢子发生及雄配子体形成过程进行了观察。结果表明：（1）雄株的小孢子发生和雄配子体发育过程正常，花药4室，花药壁由5—6层细胞组成，分别为表皮、药室内壁、中层（2—3层）和绒毡层。药壁的发育属于基本型，腺质绒毡层。（2）孢原细胞为多孢原起源。小孢子母细胞减数分裂过程中的胞质分裂为同时型，形成的四分孢子大多为四面体型，偶尔有左右对称型。同一药室的小孢子母细胞减数分裂几乎完全同步。（3）成熟花粉粒为二细胞型，具3个萌发孔。（4）两性花植株的小孢子母细胞未进行减数分裂就已退化，而且绒毡层细胞液泡化，细胞质稀少以及过度膨胀。开花时花粉囊空瘪，无花粉形成。两性花中花药败育发生在小孢子母细胞减数分裂之前，因此臭椿为形态上的雄花和两性花异株，实为功能上的雌雄异株。

Microsporogenesis and the development of male gametophyte of Ailanthus altissima（Mill.） Swingle were studied using traditional paraffin sections technology. The results showed that ： （ 1 ） In androecy, microsporogenesis and development of male gametophytes are shown normally. Its anthers have 4 microsporangiates, the wall of anther consists of five or six layers ： epidermis, endothecium, two or three middle layers and tapetum. The development of anther wall is of basic type and the tapetum belongs to glandular type. （2） Archesporium is multi-provenance. In the meiosis of micorsporocyte, cytokinesis is simultaneous; The tetrads are mostly tetrahedral, occasionally found isobilateral. Meiotic division of microsporocyte develops synchronously in each clinandrium of an anther. （3） The pollen grains with three-colpate, pollination with two-celled at the dispersal stage. （4） In hermaphroditic plants, mierospore mother cells degenerate before meiosis octouring, furthermore the large vacuole, sparse cytoplasm and expand excessively of tapetum cells are found. In anthesis, all anthers shriveled without pollen grains formation. Anthers of hermaphroditic flowers are sterile, which begin to disintegrate before the meiosis of microspore mother cell. Therefore, Ailanthus altissima （Mill.） Swingle is androdioecious morphologically, in fact it is dioecious functionally.