柴胡大、小孢子发生及雌、雄配子体发育

以柴胡(Bupleurum chinense)为研究对象, 运用石蜡切片技术对其大、小孢子发生及雌、雄配子体发育进行了研究。结果表明: 柴胡花药具4个药室, 花药壁由表皮、药室内壁、中层和绒毡层4层细胞构成, 花药壁发育为双子叶型, 腺质绒毡层。小孢子母细胞减数分裂的胞质分裂为同时型, 产生正四面体型小孢子。成熟花粉三细胞型。胚珠倒生型, 单珠被, 薄珠心。大孢子母细胞常为一个雌性孢原直接发育而成, 大孢子四分体呈线型或T型排列, 多数情况为合点端一个大孢子分化为功能大孢子, 由功能大孢子发育为蓼型成熟胚囊。在胚囊发育过程中, 珠被内表皮细胞特化成珠被绒毡层。同一朵花中, 雄蕊先熟, 记 录了花蕾大小及雌、雄配子体发育的对应关系。

Megasporogenesis, Microsporogenesis and Development of Female and Male Gametophyte of Bupleurum chinense

Paraffin wax specimens of Bupleurum chinense DC. were used to observe the whole process of embryo development, including megasporgenesis, microsporgenesis, and the development of female and male gametophytes. The anther is tetrasporangiate and its wall conforms to the Dicotyledonous type developmentally. The anther wall includes 4 layers: epiderm, endothecium, middle layer and tapetum. Simultaneous cytokinesis in the microspore mother cells follows meiosis, and the microspore tetrads are tetrahedral. Pollen grains are 3 celled when shed. The ovule is anatropous, unitegmic and tenuinucellar. Usually one archesporium functions directly as a megaspore mother cell. Cytokinesis in the megaspore mother cell usually accompanies meiosis, and the chalazal megaspore of a linear or T-shape tetrad develops into a Polygonum-type embryo sac. The innermost layer of the integument differentiates as an endothelium tapetum. In the same bud, the stamen develops earlier than the pistil. We compared the bud size and development stage of pistils and stamens.