开口箭大小孢子发生及雌雄配子体发育

Megasporogenesis,Microsporogenesis and Development of Female and Male Gametophyte of Tupistra chinensis Baker

利用石蜡切片技术,对百合科植物开口箭(Tupistra chinensis Baker)大小孢子发生及雌雄配子体发育进程进行胚胎学观察分析,以明确开口箭胚胎发育的特征,为百合科植物的研究提供生殖生物学依据。结果表明:(1)开口箭花药具有4个药室,花药壁的发育方式为基本型,由表皮、药室内壁、中层及绒毡层组成;绒毡层发育类型为分泌型,到四分体花药阶段绒毡层细胞开始解体退化,花药成熟时完全消失。(2)花粉母细胞减数分裂为连续型,依次形成二分体、四分体,四分体为左右对称形;成熟花粉为2-细胞花粉,具单萌发沟。(3)子房3室,倒生型胚珠6枚,双珠被,薄珠心;在花部的分化早期,由珠心顶端表皮下方分化出雌性孢原细胞,孢原细胞经过一次平周分裂形成周缘细胞和造孢细胞,造孢细胞发育为大孢子母细胞;大孢子母细胞第一次减数分裂后形成二分体,珠孔端的二分体孢子退化,合点端的二分体孢子继续第二次分裂,形成两个子细胞依次发育为二核胚囊、四核胚囊和八核胚囊;开口箭的胚囊发育类型为葱型。

The megasporogenesis,microsporogenesis and development of female and male gametophyte of Tupistra chinensis Baker were observed by the method of paraffin sections.The main results are follows：（1）the anther of T.chinensis Baker is four sporangiate and the development of anther wall is the basic type,and the anther wall is composed of epidermis,endothecium,middle layer and tapetum.The epidermis consisits 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 2-3layer middle layers and degenerated when maturity of the anther.The tapetum belongs to secretory tapetum and degenerated at the time of anther matured.（2）The cytokinesis of the microspore mother cells in meiosis is of successive type.The microspore tetrads are isobilateral spore.The mature pollen grain is of the 2-celled type with single germinal furrow.（3）The ovary has three chamber which has 6ovules that is double integuments,tenuinucellate and anatropous.The archesporial cell divides transversely,cutting an outer parietal cell and an inner sporogenous cell.The development of the embryo sac belongs to bisporic embryo scas.After the first meiosis,the megasporocyte divides into dyad cells and only the chalazal dyad cell undergoes the second meiotic division,whereas the micropylar dyad cell degenerates.Both the megaspore nuclei which from the functional dyad cell contribute in the formation of embryo sac.The embryo sac is of a Allum type.