南京林业大学学报(自然科学版) ›› 1982, Vol. 6 ›› Issue (03): 116-128.doi: 10.3969/j.jssn.1000-2006.1982.03.010

• 研究论文 • 上一篇    下一篇

响叶杨(Populus adenopoda Maxim)种子发育的胚胎学观察

樊汝汶;吴琼美   

  1. 南京林产工业学院林学系;南京林产工业学院林学系
  • 出版日期:1982-09-18 发布日期:1982-06-18

THE EMBRYOLOGICAL OBSERVATION OF THE SEED DEVELOPMENT OF POPULUS ADENOPODA

Fan Ruwen and Wu Qiongmei   

  1. Department of Forestry
  • Online:1982-09-18 Published:1982-06-18

摘要: <正>响叶杨花的形态特征与其他作者所报道的杨属(Populus)几个种的内容是一致的。雄蕊于小孢子母细胞时期越冬。小孢子的发生遵循被子植物的一般类型。小孢子的形成为同时型。散落时为单粒的二细胞花粉粒。 雌花芽于珠心原始体时期越冬。二心皮,子房单室,变形的侧膜胎座,每一胎座上着生一个倒生胚珠,单珠被,厚珠心。胚囊发育为蓼型,与Kimura. C等作者的观察是一致的。 珠孔受精,同李文钿在小叶杨中的观察是一致的。核型胚乳。胚胎发育为柳叶菜型。 “棉毛”是由胎座表皮细胞发育形成的,不是珠柄毛。最后还讨论了响叶杨在杨属中的分类位置。

Abstract: 1 . The floral morphological aspects of Popiilvs adenopoda Maxim correspond very closely to those of several other species of Populus reported by other workers[1,2].2 . Stamens winter in the spore-mother-cell stage and pistillate buds winter in the nucellar primordia stage. Number of carpels invariably two, the ovary unilocular with variant parietal placentae, each placenta bears one anatropous ovule.3 . Microsporogenesis follows thr usual angios-perm pattern. The fully developed anther usually shows four layers of cell wall. When mature, the cell of endotheciuin forms fibrous thickenings and the cell of tapetum is usually binucleated. The formation of microspore follows the synchronous type. Pollens shed as single grains with two-cells.4. The ovules are anatropous with unitegmic and thick nucellus. Vascullar strands pass from glacenta through funiculus, stopping at the chalazal.!i, The achesporial cell in the ovules is hypodennal in origin. There is onlly one cell in P. adenopoda. It gives birth to a parietal cell and a sporogenous cell. The megaspore mother cell is disintegrated from the primary sporogenous cell and is rather deep-seated in the nucellus as a result of the several divisions in the ^parietal cell.6 . The megaspore mother cell usually forms a linear tetrad of megaspores. The chalazal spore develops into an eight-nucleate megagametophyte (polygonum type), which corresponds very closely to what has been observed about the embryo sac of several species of Populus by Kimura, C. 3,4 During the later stages of development the megagametophyte passes through the nucellus and settles down in the micropyle.7 . With the pollen tube reaching the megagametophyte through the micropyle, double fertilization occurs. The embryo second nucleus forms before pollens enter the embryo. Division of the primary endosperm nucleus precedes that of the zygote and initiates an endosperm of the nuclear type in which walls appear only at later stages. The first division of zygote is always transverse to the long axis of the embryo sac.