江浙獐牙菜的小孢子发生和雄配子体形成及其系统学意义

Microsporogenesis and Formation of Male Gametophyte in Swertia hickinii Burk.and Their Systematical Implications

采用常规石蜡切片技术,对江浙獐牙菜(Swertia hickinii Burk)花药壁形成、小孢子发生和雄配子体形成过程进行了研究。结果表明:(1)花药四室,花药壁由表皮、药室内壁、中层和绒毡层组成,药壁发育为双子叶型。绒毡层异型起源,腺质型。花粉成熟时药室内壁径向加长并纤维状加厚,表皮宿存。(2)小孢子母细胞在减数分裂过程中胞质分裂为同时型;小孢子四分体排列方式主要为四面体型,也有左右对称型和"T"型等其他类型;成熟花粉为3-细胞型,具三萌发沟。另外,对獐牙菜属的雄性胚胎学特征进行了全面总结,并与龙胆属、蔓龙胆属及双蝴蝶属进行比较归纳出其共性。研究认为,花药表皮宿存或退化,是獐牙菜属与双蝴蝶属的重要区别之一。

Anther wall formation,microsporogenesis and the formation of male gametophyte in Swertia hic- kinii Burk. were reported for the first time in the present paper. （1）Anthers are etrasporangiate. Antherwall comprises epidermis, endothecium, one middle layer and tapetum and the development of anther wall is of the dicotyledonous type. The tapetum has dual origin and belongs to the glandular type. The endotheci- um and epidermis persist, but the cells in endothecium develop to become elongated and fibrously thick- ened. （9.）The cytokinesis in the microsporocyte meiosis is simultaneous. Most of the mierospore tetrads are tetrahedral and there are a few other types,such as isobilateral and ＂T＂-shaped. Mature pollen grains are 3- celled and tricolporate. The common embryological characters of Swertia were generalized and compared to those of Gentiana, Crawfurdia and Tripterospermurn. Whether the epidermis persists can be used to dis- tinguish Swertia from Tri pterospermura.