冬青卫矛胚珠和雌配子体的发育

 用石蜡切片的方法研究了冬青卫矛(Euonymus japonicus Thunb.)的大孢子发生和雌配子体的发育过程,得到以下结果:①胚珠发生为厚珠心类型,珠心表皮细胞平周分裂产生多层珠心周缘细胞,胚珠有直生与倒生胚珠2种类型,具双珠被,珠孔在成熟胚囊时期为内外珠被共同形成;②胚珠内孢原细胞为单细胞,并直接分化为大孢子母细胞,大孢子发生时,珠孔端一个细胞不分裂,合点端的一个细胞正常分裂,大孢子发育三分体,为直线型排列.③胚囊发育为蓼型,胚囊成熟后为7细胞8核胚囊,胚囊合点端有承珠盘.开花前,两极核融合为一个次生核,反足细胞退化较晚.

Development of ovule and female gametophyte in Euonymus japonicus Thunb

The megasporogenesis and development of female gametophyte in Eunymus japonicus were studied by the parraffin section method.The results areas follows:①The ovule is crassinucellar,the nucellar epidermal cell cuts off several layer nucllar parietal.The ovule is bitegminy,anatropous and orthotropous.The micropyle is made up of an outer and inner integument;②A single archesporal cell differentiates immediately below the nucellar epiderm,it functions directly as the megaspore mother cell.During megasporogenesis,the dyad cell near micropyle doesn’t divide,however,the other cell beside the chalaza splits nomally,thus it makes megaspore triad,the triad arrange in a straight line or in a"T"shape;③Its embryo sac is Polygonum type.The mature embryo sac has seven cells and eight nuclei or seven nuclei,and a cap shaped hypostases is present in mature ovule.Two polar nuclei fuse into the secondary nucleous.Three antipodal cellls degenerate lately.