海桐大、小孢子发育及雌、雄配子体形成的研究

Megasporogenesis and microsporogenesis as well as male and female gametophyte development of Pittosporum tobira

关键词:  海桐  大孢子发生  小孢子发生  雄配子体  雌配子体

Key words:  Pittosporum tobira  megasporogenesis  micrasporogensis  male gametophyte  female gametophyte

摘要:

利用常规石蜡制片法研究了海桐大、小孢子发生及雌、雄配子体发育的过程。结果显示:(1)小孢子母细胞减数分裂过程中的胞质分裂为连续型,四分孢子为以四面体形为主,四分孢子后期部分小孢子壁皱缩;(2)花药壁由4层结构组成,由外到内为表皮、药室内壁、中层和绒毡层;(3)海桐具多个胚珠,单珠被,薄珠心,胚珠类型为倒生胚珠。大孢子母细胞减数分裂主要形成线形排列的4个大孢子,还具有少有的十字形排列,功能大孢子位于合点端;(4)胚囊发育属单孢型的蓼型,成熟的雌配子体为四细胞五核胚囊。

Abstract:

This paper describes megasporogenesis and microsporogenesis as well as male and female gametophyte development of Pittosporum tobira(Thunb.)Ait. by using nomal paraffin method. The results are as follows:(1)cytokinesis in the process of meiotic division of microsporocyte is successive type,the main arrangement of microspores tetrad is tetrahedral, and wall of some microspores are shriveled at the last stage of microspores tetrad;(2)the anther wall is composed of 4 layers,which are epidermis,endothecium,middle layer and tapetum;(3)an ovary locules has many ovules,which are unitegmic,tenuinucellate and anatropous. Four megaspores divided from megasporocyte arrange in line during tetrad period,and some in decussate,the chalazal megaspore is functional;(4)the development of embryo sac was polygonum type which belongs to the bisporic embryo sac.Most mature embryo sac are 5-nucleated embryo sac which the 5 nuclei belong to 4 cells.