瘿椒树大小孢子发生及雌雄配子体发育解剖学研究

Anatomical Studies on Megasporogenesis,Microsporogenesis and Development of Female and Male Gametophyte in Tapiscia sinensis Oliver

采用半薄切片和常规石蜡切片技术,对瘿椒树(Tapiscia sinensis Oliver)的大小孢子发生及雌雄配子体发育过程进行观察研究。结果显示:(1)瘿椒树花药壁发育为基本型,周缘细胞平周分裂2次成为4层细胞,其中有些细胞仍能进行一次平周分裂,最后分别发育成药室内壁、中层和绒毡层,绒毡层为分泌型。(2)小孢子母细胞减数分裂过程中的胞质分裂为同时型,产生四面体型四分体。雄花成熟花粉为二细胞型,两性花花粉败育。(3)子房为1室1胚珠,双珠被,厚珠心,基生胎座,倒生型胚珠。大孢子母细胞减数分裂产生三分体和少量线形四分体,合点端大孢子为功能大孢子。其雌配子体发育为蓼型。成熟胚囊里,反足细胞早期退化,极核融合为次生核移向合点端,附着在合点端珠心细胞分裂形成的突起上,为胚囊发育的特殊结构。结果表明,瘿椒树花为单性花,且雌雄异株,比省沽油科其它属植物较为进化。因此,支持将瘿椒树属(Tapiscia)提升为瘿椒树科(Tapisciaceae)。

The process of megasporogenesis,microsporogenesis and the development of female and male gametophyte of Tapiscia sinensis Oliver were observed by semi-thin section and serial paraffin sections. The results are as follows： （1） the development of the anther wall belongs to a basic type. By 2 periclinal cell divisions,the primary parietal layer produces 4 layer,which finally developed into four structural layers,epidermis,fibrous endothecium,one middle layer and tapetum from outer to inner. During this course, some cells of the 4 layers show the ability of periclinal cell division. Tapetum cell is of a secretary type. （2）In microsporocyte meiosis,the cytoplasm division is of simultaneous type and the tetrad is tetrahedral. The mature pollen in maleflower belongs to two-cell type, but the pollen in bisexualflower is abortion. （3）The ovary has one chamber which has one ovule that is double integuments, crassinucellate and anatropous. After meiosis, the megasporocyte divides into triad in line type or rarely divides into four megaspores in line type. The megaspore in chalaza end usually is functional one. The embryo sac is of a polygonum type. In mature embryo sac,antipodal cell degenerates early,after two polar nuclei fused, the secondary nucleus moves to chalaza end,attached on bowl protuberance in chalaza end, this is a peculiar structure in its development. As a result,the flower of Tapiscia sinensis Oliver is unisexual flower and dioecism that it is more advanced than plants of Staphyleaceae. Therefore,Our studies of embryology in Tapiscia sinensis supports the hypothesis that Tapiscia should be raised to family level.