獐牙菜小孢子发生及雄配子体发育

Microsporogenesis and the development of male gametophyte in Swertia bimaculata

关键词:  獐牙菜  小孢子  雄配子体

Key words:  Swertia bimaculata  microspore  male gametophyte

摘要:

用石蜡切片法对獐牙菜小孢子发生及雄配子体发育过程进行首次观察研究。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2层；药室内壁同表皮同时宿存，细胞柱状伸长，纤维状加厚。小孢子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，少数为左右对称形和十字交叉形；成熟花粉多为2 细胞类型，偶见3 细胞型，具三萌发孔。

Abstract:

Microsporogenesis and the development of male gametophyte in Swertia bimaculata were studied by the method of paraffin section for the first time in the present paper. The main results can be concluded as follows:Anthers are tetrasporangiate，the development of anther walls conforms to the basic type and comprises of epidermis，endothecium，two middle layers and tapetum at mature stage. The tapetum has dual origin and belongs 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. Two middle layers are ephemeral；endothecium and epidermis persists and develops to become fibrous thickening. The cytokinesis of the microspore mother cell 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. Pollen grain is mainly 2 celled type when shed，occasionally 3 celled type，and it has three apertures.