七叶树小孢子发生及雄配子体发育研究

Microsporogenesis and Male Gametogenesis in Aesculus chinensis Bunge

用石蜡切片法观察了七叶树花药的发育过程.结果表明：（1）雄蕊花药四室,花药壁完全分化时,从外到内依次是表皮、药室内壁、中层和绒毡层,花药壁发育为基本型.表皮细胞1层,发育过程中始终存在;药室内壁在花药成熟时形成带状纤维层加厚;幼小花药壁的中层3~4层细胞,在花药发育成熟时退化消失;绒毡层1层细胞,发育类型为分泌型,小孢子母细胞减数分裂时绒毡层开始退化解体,花药成熟完全消失,仅剩1层绒毡层膜.每一花药中有多列雄性孢原细胞,发生于幼小花药表皮下方;（2）小孢子母细胞减数分裂为同时型,四分体多呈正四面体排列;减数分裂过程中,小孢子母细胞外方被胼胝质壁所包被,小孢子形成后胼胝质壁逐渐消失.成熟花粉二细胞型,外形呈圆三角状,具三孔沟.

The microsporogenesis and development of male gametophyte of Aesculus chinensis Bunge were observed by the method of paraffin sections.The main results as follows：The anther is 4 sporangiates and the development of anther wall is the basic type,which is composed of epidermis,endothecium,middle layer and tapetum.The epidermise consist of one layer of cells and still existed as the anther matured.The endothecium developed banding-shaped thickenings when the anther matured.The young anther wall has 3～4 layer middle layers and degenerated when maturity of the anther.The tapetum has dual origin and belong to secretory type,which degenerated just leavening the tapetal membrane at the time of anther matured.The archesporium derived from the cell under the epidermis.The cytokinesis of the microspore mother cells in meiosis is simultaneous.Most of the microspore tetrads are tetrahedral and lest of them are isobilateral.The walls of the microspore mother cells become thicker by the deposition of callose at the time of meiosis and the callose wall were degenerated at the time of microspores.Mature pollen grain is the 2-celled type with three germinal furrows.