摘要
本文运用石蜡切片、酶解压片、酶解一整体解剖方法,对党参(Codonopsis pilosula Nannf.)的大、小孢子发生;雌、雄配子体发育;胚及胚乳的发育进行了初步观察。1.幼嫩花药的药壁由表皮、药室内壁、中层、绒毡层4层细胞组成,药壁发育为双子叶类型。绒毡层具双重起源和异型性,细胞单核或双核,属分泌型绒毡层。孢原细胞为一列多孢原。小孢子母细胞由初生造孢细胞直接发育而来,其减数分裂中的孢质分裂为同时型,四分体的排列为四面体型。成熟花粉为二细胞型。2.子房为3心皮,3室,多胚珠,中轴胎座,薄珠心,单珠被,倒生型胚珠。孢原细胞一个。大孢子母细胞减数分裂形成线形排列的4个大孢子,其中合点端的大孢子具功能。胚囊发育为蓼型。极核在受精前融合为次生核,反足细胞在受精前已退化。3.异花传粉,珠孔受精。精核与次生核的融合快于精核与卵细胞核的融合。4.胚乳为细胞型。胚乳细胞前3次分裂有一定规律。8细胞胚乳以后,近珠孔端与合点端的两个胚乳细胞不经分裂而发育为吸器,至球胚晚期吸器退化。成熟种子具丰富的胚乳。5.胚胎发育属茄型。胚柄子球胚晚期开始退化。其胚发育历经原胚期、心形胚期、鱼雷胚期至成熟胚。
This paper reports the studies of megasporogenesis and microsporogenesis,development of female and male gametophytes,fertilization,and development of embryo and endosperm, The anther wall consists of four layers,i.e.epidermis,endothecium,middle layer and tapetum. Part of the tapetum cells originates from the primary parietal cells,and the other part comes from the basic tissue of the anther partition.Tapetal cells are uninucleate or binucleate,and belong to the secretory type.Microsporocyte originates directly from the primary sporogenous cell,Cytokinesis is of the simultaneous type.Arrangement of microspores in tetrad is isobila- teral.Mature pollen grain is of the 2-celled type.The ovary is tricarpellum,trilocular with many ovules.The ovule is mono-integinous,tenui-nucellar and anatropous.The embryo sac ori- ginates from the single-archesporial cell.The one chalazal megaspore in linear tetrad is the functional megaspore.The development of embryo sac is of the Polygonum type.Before fer- tilization,two polar nuclei fuse in to a secondary nucleus and the antipodal cells degenerate. Fertilization is porogamy,fusion of one sperm with secondary nucleus is faster than that of one sperm with egg nucleus.The development of endosperm is of the cellular type.The first three divisions of endosperm cells are regular.Two endosperm cells near the ends of chalaza and the micropyle develop into haustorium without division.The haustoria gradually dege- nerate at the late stage of globular embryo.The mature seeds contain abundant endosperm. The development of embryo is of the Solanad type.The suspensor consists of 12—20 cells. The optimum development of the suspensor is at the early stage of the globular embryo.It begins to degenerate after late globular stage.The embryo develops from proembryo,heart- shaped embryo,dicotyledenous- to mature embryo.
基金
国家自然科学基金资助课题
关键词
党参
胚胎学
Codonopsis pilosula Nannf
Embryology
