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1.
对湖北双蝴蝶大孢子发生、雌配子体形成、受精、胚及胚乳发育过程进行了解剖学观察研究.结果显示:(1)子房2心皮,1室-侧膜胎座,薄珠心,单珠被,倒生胚珠,胚珠列数为4列;大孢子母细胞减数分裂形成的4个大孢子多呈直线形排列,少数为"T"形四分体,合点端的大孢子具功能;胚囊发育为蓼型;3个反足细胞宿存至8-细胞原胚.(2)珠孔受精;胚乳发育为核型;胚发育为茄型.(3)果实成熟时,种子发育至球形胚阶段.  相似文献   

2.
对湖北双蝴蝶大孢子发生、雌配子体形成、受精、胚及胚乳发育过程进行了解剖学观察研究。结果显示:(1)子房2心皮,1室,侧膜胎座,薄珠心,单珠被,倒生胚珠,胚珠列数为4列 大孢子母细胞减数分裂形成的4个大孢子多呈直线形排列,少数为“T”形四分体,合点端的大孢子具功能 胚囊发育为蓼型 3个反足细胞宿存至8-细胞原胚。(2)珠孔受精 胚乳发育为核型 胚发育为茄型。(3)果实成熟时,种子发育至球形胚阶段。  相似文献   

3.
李鹂  黄衡宇 《广西植物》2015,35(5):631-640
利用石蜡切片技术,对川东獐牙菜(Swertia davidii)的胚胎发育过程进行显微观察,并根据现有资料,对獐牙菜属的几种植物进行了比较胚胎学研究。结果表明:川东獐牙菜花药四室,药壁发育为基本型,绒毡层异型起源,为腺质绒毡层,发育后期药室内观察到的绒毡层核是早期该层细胞有丝分裂凸入药室并原位退化形成的,中层细胞3层,药室内壁退化,花药壁表皮宿存,细胞柱状伸长,纤维状加厚;小孢母细胞减数分裂为同时型,四分体排列方式主要为四面体形和左右对称型,少数为"T"形和十字交叉形,成熟花粉为2-细胞类型;子房2心皮、1室,侧膜胎座;薄珠心,单珠被,倒弯生胚珠,大孢子母细胞减数分裂形成4个大孢子直线形排列,合点端的大孢子具功能,雄配子体发育为蓼型;2个极核在受精前融合为1次生核,合点端3个反足细胞宿存,每个细胞均多核和异常膨大,形成明显的反足吸器,并在胚乳之外形成染色较深的类似"外胚乳"结构;珠孔受精,受精作用属于有丝分裂前类型;胚乳发育为核型,胚胎发育为茄型;果实成熟时,种子发育至心形胚阶段;反足细胞在龙胆科一些短命植物中的宿存与分裂具有重要的生殖适应与进化意义。  相似文献   

4.
喉毛花的胚胎学研究   总被引:9,自引:0,他引:9  
本文首次系统地记载了喉毛花属的胚胎发育过程,并以此为依据讨论了该属的分类等级和系统位置。喉毛花花药四室;药壁发育属双子叶型;绒毡层单型起源,细胞具单核,属腺质绒毡层;一层中层细胞;花药壁表皮层宿存,纤维状加厚和膨大;药室内壁减缩。小孢子母细胞减数分裂为同时型,四分体的排列为四面体型;成熟花粉为3-细胞型。子房为2心皮、l室,典型的侧膜胎座,胚珠8列,胚珠胎座靠近两心皮腹缝线。薄珠心,单珠被,倒生胚珠。大孢子母细胞减数分裂形成的4个大孢子呈直列式排列,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。反足细胞宿存、分裂为8~12个,每个细胞均多核和异常膨大,反足细胞形成的吸器明显。异花传粉,珠孔受精。花粉管通过破坏一助细胞进入胚囊。受精作用属于有丝分裂前配子体融合类型。胚乳发育为核型,每核含2~3核仁。胚胎发育为茄型酸浆I变型,成熟种子胚只发育至球形胚阶段。反足细胞在合子分裂之后才开始退化,在胚的发育过程中反足细胞在胚乳层之外形成一层染色深、类似“外胚乳”的结构。比较喉毛花、龙胆属、假龙胆属以及肋柱花属的胚胎学特征表明喉毛花与假龙胆属的亲缘关系最近,在分类等级上作为一个独立的属较为合适,在系统位置上它比假龙胆属更为原始。  相似文献   

5.
掌叶大黄胚胎学研究   总被引:3,自引:0,他引:3  
掌叶大黄(Rheum palmatum L.)的花药4室,单或复孢原。药壁发育为单子叶型。腺质绒毡层发育后期出现双核。小孢子四分体为四面体型,胞质分裂为同时型。成熟花粉为3细胞,表面具3条沟。子房1室,单胚珠,直生,两层珠被,由内珠被形成珠孔,厚珠心。单孢原,位于珠心表皮下。直线形或T形大孢子四分体。合点端的大孢子发育为蓼型胚囊。2个极核在受精前合并为次生核。3个反足细胞宿存。胚乳发育为核型,在球形胚末期开始形成细胞。合点端的胚乳核一直不形成细胞,而为游离核的胚乳吸器。在胚乳吸器和其它部位都发现胚乳核融合现象。胚的发育属于紫菀型。胚具小胚柄。成熟胚囊时期出现承珠盘,且存留时间很长,成熟胚期尚存痕迹。  相似文献   

6.
小蓬草的胚胎学研究   总被引:2,自引:0,他引:2  
对小蓬草(Conyzacanadensis)大小孢子发生、雌雄配子体形成、受精、胚及胚乳发育过程进行了研究,主要结果如下:花药四室,药壁由表皮、药室内壁、中层和绒毡层组成。表皮退化;药室内壁宿存,细胞柱状伸长,纤维状加厚;中层细胞退化较早,在小孢子母细胞减数分裂开始时仅存残迹;绒毡层于小孢子母细胞减数第一次分裂前期开始原位变形退化,属于腺质型绒毡层;小孢子母细胞减数分裂为同时型,四分体的排列方式主要为四面体形和左右对称形;成熟花粉粒多为3-细胞花粉粒,偶见2-细胞花粉粒。子房下位,2心皮,1室,单胚珠,基生胎座;单珠被,薄珠心,倒生胚珠,具发达的珠被绒毡层。珠心表皮下分化出大孢子孢原细胞,孢原细胞直接发育为大孢子母细胞,大孢子母细胞减数分裂形成4个大孢子直线形排列,仅合点端的大孢子发育成功能大孢子母细胞,胚囊发育为蓼型。两个极核在受精前融合为次生核,珠孔受精。胚乳发育属于核型,胚胎发育为紫菀型;具胚乳吸器。  相似文献   

7.
高山红景天胚胎学研究   总被引:8,自引:4,他引:4  
张萍  申家恒 《植物研究》1998,18(1):38-45
高山红景天(Rhodiola sachalinensis A.Bor.)具8个雄蕊,每个雄蕊有4个花粉囊。小孢子母细胞减数分裂时,胞质分裂为同时型。形成的四分体为四面体形。花药壁由表皮、药室内壁、二层中层和绒毡层五层细胞组成,其发育方式为基本型。腺质型绒毡层,有些绒毡层细胞分裂形成不规则双层,少数细胞双核。二细胞型花粉。雌蕊由4心皮组成。边缘胎座,倒生胚珠,双珠被,厚珠心,胚珠发育中形成珠心喙。大孢子四分体线形或T -形,合点大孢子具功能。胚囊发育为蓼型。成熟胚囊中,卵细胞核、助细胞核均位于细胞的合点端,珠孔端具液泡;极核融合为次生核,并位于卵细胞合点端附近; 3个反足细胞退化。双受精属于有丝分裂前配子融合类型。胚的发育为石竹型;基细胞侵入珠孔端,形成囊状吸器。细胞型胚乳;初生胚乳核分裂形成两个细胞,其珠孔端的细胞发育成胚乳本体,合点端的细胞直接发育成具一单核的合点吸器。  相似文献   

8.
对小蓬草(Conyza canadensis)大小孢子发生、雌雄配子体形成、受精、胚及胚乳发育过程进行了研究,主要结果如下:花药四室,药壁由表皮、药室内壁、中层和绒毡层组成.表皮退化;药室内壁宿存,细胞柱状伸长,纤维状加厚;中层细胞退化较早,在小孢子母细胞减数分裂开始时仅存残迹;绒毡层于小孢子母细胞减数第一次分裂前期开始原位变形退化,属于腺质型绒毡层;小孢子母细胞减数分裂为同时型,四分体的排列方式主要为四面体形和左右对称形;成熟花粉粒多为3细-胞花粉粒,偶见2细-胞花粉粒.子房下位,2心皮,1室,单胚珠,基生胎座;单珠被,薄珠心,倒生胚珠,具发达的珠被绒毡层.珠心表皮下分化出大孢子孢原细胞,孢原细胞直接发育为大孢子母细胞,大孢子母细胞减数分裂形成4个大孢子直线形排列,仅合点端的大孢子发育成功能大孢子母细胞,胚囊发育为蓼型.两个极核在受精前融合为次生核,珠孔受精.胚乳发育属于核型,胚胎发育为紫菀型;具胚乳吸器.  相似文献   

9.
通过研究山薯的雌花及胚胎发育,为山薯的胚胎学研究以及杂交育种奠定基础。结果表明:山薯大部分为雌雄异株,海南岛的山薯雌花花期约3个月,为9月初至11月末。子房3室,每室有2个倒生胚珠;胚珠具厚珠心,双珠被。珠孔一端表皮下的孢原细胞逐渐发育为大孢子母细胞。大孢子母细胞减数分裂形成4个呈线形排列的大孢子,其中只有1个可以发育为功能大孢子。成熟的胚囊为7胞8核胚囊,其胚囊发育类型为蓼型。卵细胞的受精属于有丝分裂前型。其胚的发育类型为柳叶菜型,经过二细胞原胚、倒T型原胚、棒状胚、球形胚和梨形胚这5个发育阶段。胚乳的发育为核型。  相似文献   

10.
白桦雌花发育、大孢子发生及胚胎发育的解剖学观察   总被引:6,自引:2,他引:4  
姜静  李同华  庄振东  杨传平 《植物研究》2003,23(1):T007-T009
白桦雌花从开花到雌性器官的成熟需经历1个月左右的时间,解剖学观察表明:四月下旬越冬的雌蕊原基开始了活跃的分裂和分化。子房和柱头开始生长。四月末开花,五月初授粉。此后胚珠开始长大。五月中旬即分化形成珠被,珠心,珠被为单层珠被,胚珠为厚珠心胚珠,胚珠倒生,五月中下旬,珠心内产生大孢子母细胞,一周左右发育为成熟胚囊-七细胞八核胚囊,五月末完成双受精,白桦胚胎发育经过合子,原胚,球形胚,心形胚和鱼雷形胚等时期最后发育成熟,胚乳发育与胚胎同步,即受精的极核进行几次分裂后形成核型胚乳,胚乳核不断增多,在形成心形胚后胚乳细胞形成细胞壁。  相似文献   

11.
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. Tapeta? 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 isobilateral. 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 originates 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 fertilization, 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 ceils are regular. Two endosperm cells near the ends of chalaza and the micropyle develop into haustorium without division. The haustoria gradually degenerate 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, heartshaped embryo, dicotyledenous- to mature embryo.  相似文献   

12.
用常规石蜡制片对黄顶菊(Flaveria bidentis(L.) Kuntze)大孢子发生、雌配子体和胚胎的发育过程进行了观察.黄顶菊雌蕊柱头二裂,2心皮,1室,单胚珠,基生胎座,单珠被,薄珠心,倒生胚珠,具发达的珠被绒毡层.珠心表皮下分化出孢原细胞,孢原细胞直接发育为大孢子母细胞,大孢子母细胞减数分裂形成直列四分体...  相似文献   

13.
This is one of a series of studies on the reproductive features in Cimicifuga nanchuanensis Hsiao, an endangered plant endemic to China, and C. simplex Wormsk, a closely related and widely spread species as a control. The present paper deals with the results of cyto-morphological observations on the megasporogenesis, the development of female gametophytes, and the embryogeny in C. simplex. Its anatropous ovules are bitegminous and crassinucellate. A megaspore mother cell undergoes meiosis to form a linear or T-shaped megaspore tetrad. The embryo sac is of Polygonum type. The three antipodal cells persist up to the globular stage of embryo development.Two polar nuclei fuse to form a secondary nucleus close to the chalazal end of the embryo sac and connect with antipodal cells before fertilization. The development of endosperm is of Nuclear type. Cellularization of nuclear endosperm initiates since early globular stage of the embryo development. Development of the embryo in C. simplex is of Onagrad type. C. simplex is dichogamous. Stigmatic papillae emerge on the 1st∽2nd day and they elongate into stigmatic hairs on the 3rd∽5th day after stamens withering. The great impact of the differences of the receptible period of stigmas and pollen viabilitybetween the two species on effective pollination and seed-setting rate is discussed.  相似文献   

14.
Megasporogenesis and embryo sac development in Stellaria media were investigated using cytochemical methods for the demonstration of nucleic acids, proteins, and polysaccharides. RNA concentrations were high in the archesporial cells, low in the megaspore mother cell, and increased again to high concentrations with the formation of the megaspore and 2-, 4-, and early 8-nucleate embryo sac. RNA levels were also high in the egg and primary endosperm nucleus but low in the synergid and antipodal cells. Nucleolar size and vacuolation were indicative of RNA synthetic activity. Protein concentrations were parallel in concentration and distribution to those observed for RNA. Polysaccharides were conspicuously absent from all stages except the synergids and nucellar cells. Feulgen-stained DNA was demonstrable in the antipodal cells, megaspore mother cell, and megaspore cell, but was not visible in the 2-, 4-, or early 8-nucleate embryo sac. Feulgen staining was also absent from the egg and primary endosperm nucleus but was visible in the synergids and antipodals. Histones were difficult to visualize anywhere except in the egg cytoplasm and the nuclei of the antipodals.  相似文献   

15.
The megasporogenesis, female gametophyte development and embryonic development of Ambrosia artemisiifolia L. and Ambrosia trifida L. of genus Ambrosia L. in China were studied using conventional paraffin section technology and optical microscopy. The results show that both A. artemisiifolia L. and A. trifida L. have a bilobed pistil stigma, two carpels, one chamber, basal placenta, unitegmic, tenuinucellate, anatropous ovule, and well-developed integumentary tapetum. Megaspore mother cells are directly developed from archesporial cells originated from the nucellar cells under the nucellar epidermis and further undergo meiosis to form linear tetrads. The megaspore at the chalazal end develops into a functional megaspore and the other three megaspores are degraded. The development of embryo sac is monosporic type. After three consecutive mitosis, mononucleate embryo sac becomes a mature embryo sac with two synergids and one egg cell at the micropylar end, a central cell at the center and three antipodal cells at the chalazal end. Most antipodal cells are mononucleate or binucleate, only few are trinucleate. The embryonic development process contains four stages: globular embryo, heart-stage embryo, torpedo-stage embryo and mature embryo. The development of endosperm is cellular type.  相似文献   

16.
The nucellus of Machaeranthera pattersonii (A. Gray) Greene (Aster pattersonii A. Gray) contains only one megaspore mother cell, and the female gametophyte develops from the chalazal megaspore of a row of four, thus conforming to the Polygonum type of development. These observations are contrary to the older work of Palm. Three nuclear divisions produce the typical eight nuclei with the egg apparatus, primary endosperm cell with two polar nuclei, and two antipodal cells, the micropylar one containing two nuclei. Usually no more antipodal cells are formed, although there is further nuclear division, apparently followed by nuclear fusion. The antipodal cells remain about the same size without forming an antipodal haustorium. Cell division accompanies the first division of the primary endosperm nucleus. The early stages of the embryo resemble those of other Compositae. Machaeranthera tanacetifolia (HBK) Nees also shows the Polygonum type of development of the female gametophyte. It is suggested that Palm may have been working on some species of Erigeron that had been wrongly identified, which would account for the difference in observations.  相似文献   

17.
荔枝的胚胎学研究   总被引:11,自引:1,他引:10  
  相似文献   

18.
韭菜胚囊发育与胚胎发生   总被引:2,自引:0,他引:2  
韭菜胚囊发育为葱型,胚胎发生属柳叶菜型。成熟胚囊中,三个反足细胞形态上常类似卵器,其中二个呈助细胞状,一个呈卵细胞状。卵状反足细胞可分裂成多细胞原胚,但随着胚乳的发育而退化。在未受精胚囊中,卵细胞和卵状反足细胞均可分裂,它们的发生过程与合子胚相似,但因无胚乳哺育,均不能继续发育。论证了反足细胞胚的性质,初步探讨了胚乳与反足细胞无配子生殖的关系。  相似文献   

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