川东獐牙菜小孢子发生和雄配子体形成

报道了川东獐牙菜（Swertia davidii Franch.）小孢子发生和雄配子体形成的过程。主要结果如下：花药四室，药壁发育为基本型；绒毡层异型起源，属于腺质型绒毡层，药室内具有的退化绒毡层核是早期该层细胞有丝分裂凸入药室中央并原位退化形成的；中层细胞3层；药室内壁退化；花药壁表皮宿存，细胞柱状伸长，纤维状加厚。小孢母细胞减数分裂为同时型，四分体排列方式主要为四面体形和左右对称型，少数为“T”形和十字交叉形；成熟花粉为2-细胞类型。

The genesis of microspore and the formation of male gametophyte in Swertia davidii Franch.

The present paper firstly reports the microsporogenesis and the formation of male gametophyte in Swertia davidii Franch..The main results showed that anther is tetrasporangiate.The development of anther walls conforms to the Basic type and comprises of epidermis, endothecium, three middle layers and tapetum at the mature stage. The tapetum cells have dual origin and belong to the glandular type. The degenerating tapetum nuclei in the middle of anther locules are from the tapetum cells, which undergo mitosis, then intrude into the anther locules and degenerate in situ at the early stage. Three middle layers are ephemeral. Endothecium degenerates shortly after differentiating; epidermis persists and develops to become histogram elongated and fibrous-thickening. The cytokinesis of the microspore mother cells in meiosis is of the Simultaneous type. Most of the microspore tetrads are tetrahedral and there are still a few other types, such as isobilateral, dilateral and "T"-shaped. Pollen grains are 2-celled when shed.