Megagametophyte development of Nymphaea nouchali Burm. f. (Nymphaeaceae)

The development of reproductive cells has been analysed in Nymphaea nouchali , family Nymphaeaceae, subclass Magnoliidae. Our observations on embryo sac development differ from those in the literature. Megasporogenesis results in a triad of one micropylar cell and two innermost megaspores. Embryo sacs derive from a single functional megaspore and are tetranucleate. Megasporogenesis is monosporic and of the Polygonum type, but mega-gametogenesis is of Oenothera type.     

无距虾脊兰胚珠发育及种子形成研究

采用石蜡切片、半薄切片、扫描电镜技术对无距虾脊兰不同时期的子房(蒴果)进行研究.结果表明:(1)无距虾脊兰授粉后19d,胎座上分化出上万个胚珠原基,这些胚珠原基由1列细胞外包1层表皮细胞构成,其中胚珠原基内部顶端的细胞分化为孢原细胞,授粉后45 d,孢原细胞发育分化为大孢子母细胞.(2)无距虾脊兰成熟胚珠为倒生胚珠,双珠被,薄珠心,胚囊发育为蓼型,且胚珠的发育即便在同一个果实内也是不同步的.(3)受精后合子经过一次不均衡横裂形成基细胞和顶细胞;基细胞不参与胚体构成,分化为单细胞的胚柄,最后退化消失;顶细胞经多次分裂形成原球胚,胚胎发育类型为石竹型.(4)成熟种子呈纺锤形,由球形胚和内外双层种皮构成,双层种皮分别由内外珠被发育而来.     

楸树大小孢子发生与雌雄配子体发育的研究

运用石蜡切片法和整体透明法对楸树(Catalpa bungei C.A.Meyer)大、小孢子发生及雌、雄配子体发育过程进行了研究.结果表明:楸树可育雄蕊2枚,花药4室,药壁发育属双子叶型,腺质异型绒毡层.小孢子母细胞减数分裂为同时型,四分体后小孢子不分离形成正四面体型四合花粉,偶有左右对称型和十字交叉型.成熟花粉为二细胞型,无萌发孔.子房上位,2室,中轴胎座,胚珠多数,倒生,单珠被,薄珠心,具珠被绒毡层.单孢原直接发育为大孢子母细胞,四分体线形排列,合点端大孢子发育为功能大孢子,胚囊发育为蓼型.雄蕊发育早于雌蕊,花开后雌、雄蕊趋于同熟.研究认为:虽然楸树雌、雄蕊发育过程中均存在一定比例的败育,但其花而不实"并非雄性或雌性不育所致.推测与其授粉受精和胚后发育有关.     

Development and ultrastructure of the megagametophyte in Passiflora caerulea L. (Passifloraceae)

Megasporogenesis and megagametogenesis of Passiflora caerulea L. were studied using light and transmission electron microscopy. The archesporial tissue is generally formed by one cell. The megaspore mother cell gives rise to a linear tetrad of megaspores. The chalazal megaspore is the functional one, and originates a Polygonum -type female gametophyte. The antipodals are ephemeral. Abundant starch is found in the nucellar cells, specially the ones adjacent to the megagametophyte. The two synergids show ultrastructural differences, involving the filiform apparatus, the nucleolus and the endoplasmic reticulum; these differences suggest a functional differentiation, probably related to the reception of the pollen tube. This is the first report in angiosperms of substantial morphological differences between the two synergids.  © 2003 The Linnean Society of London, Botanical Journal of the Linnean Society , 2003, 142 , 73–81.     

柽柳大、小孢子发生和雌、雄配子体发育的观察

利用常规石蜡制片技术,对柽柳(Tamarix chinensis Lour.)的大、小孢子发生及雌、雄配子体发育过程进行了观察。主要结果如下:(1)花药壁由五层细胞组成,从外向内分别为表皮、药室内壁,两层中层和绒毡层。药壁的发育属于基本型。绒毡层为分泌型。(2)孢原细胞为多孢原起源。小孢子母细胞减数分裂过程中的胞质分裂为连续型,形成的四分孢子为四面体型;同一药室的小孢子母细胞减数分裂几乎完全同步。(3)成熟花粉粒为2细胞型,具3个萌发孔。(4)柽柳为三心皮构成的单室复子房,每子房具有10~20个胚珠,基底胎座,胚珠为双珠被、厚珠心、倒生型。大孢子母细胞减数分裂形成1+3排列的4个大孢子, 4个大孢子全部参与胚囊的形成。(5)胚囊发育为贝母型,反足细胞在胚囊成熟时充分发育。(6)同一朵花中,前期雄蕊的发育早于雌蕊的发育,后期当花粉成熟时,雌配子体也达到成熟,雌雄蕊发育趋于同步。     

矮沙冬青雌配子体及胚胎发育研究

矮沙冬青子房单心皮1室,边缘胎座,弯生胚珠,胚珠具双珠被、厚珠心。大孢子孢原细胞发生于珠心表皮下,大孢子母细胞减数分裂形成直线排列的四分体,合点端大孢子具功能,并按蓼型胚囊发育,雌配子体成熟于4月中旬。双受精后,胚乳发育为核型。在矮沙冬青大孢子发生、雌配子体和胚胎发育过程中未发现异常现象,因此认为矮沙冬青濒危不存在雌性生殖结构与发育过程异常的内在因素。     

Ovule and seed development of Lacandonia schismatica (Lacandoniaceae)

Ovule and seed development is described for Lacandonia schismatica, a species whose androecium is surrounded by the gynoecium. The ovule in each carpel is basal, anatropous, tenuinucellate, and bitegmic. The female gametophyte is formed by the micropylar megaspore cell, after a coenocytic stage of the four megaspore nuclei. The mature female gametophyte has the normal complement of seven cells and eight nuclei. We propose a new type of female gametophyte development on the basis of the coenocytic stage of the tetrad, the cellularization of the tetrad, and the survival of the micropylar spore. At seed dispersal time, the embryo has ~10-20 cells. Endosperm development is of the nuclear type. At maturity, endosperm cells show starch and protein inclusions as well as polysaccharides in their thick walls. The seed coat is formed from the outer integument; the inner one disappears. The exotesta contains tannin. The fruit (achene) wall is two-layered. The maturation of the fruits in a flower is synchronous, and they separate from the receptacle for dispersal.     

依兰(番荔枝科)雌配子体发育研究

荔枝科是被子植物的基部类群之一,依兰属是番荔枝科较为原始的类群,其有性生殖过程,特别是胚胎发生与发育的研究结果,可以补充被子植物胚胎学原始特征的相关基础资料。该研究利用常规石蜡切片技术,对依兰胚珠、大孢子和雌配子体的发生发育过程进行了观察。结果表明:依兰的胚珠为倒生胚珠、厚珠心、三层珠被,第三层珠被(中间珠被)发生在大孢子母细胞时期,于外珠被与内珠被之间、胚珠合点端两侧发生并隆起;雌配子体为蓼型。此外,依兰的个别胚珠中存在双雌配子体现象,且两个雌配子体均由大孢子母细胞发育而来,大小、形状相近,呈线形排列。该研究结果对于揭示原始被子植物胚胎发育特征具有重要意义。     

小盐芥大孢子发生和雌配子体发育

本论文研究了小盐芥（Thellungiella halophila）大孢子发生和雌配子体发育过程及该阶段与花蕾、花、果实外部形态的相关性。结果如下：小盐芥雌蕊由2心皮组成,侧膜胎座,每室胚珠多数,弯生,双珠被,薄珠心。孢原细胞位于珠心表皮之下,直接起大孢子母细胞的功能。大孢子四分体线形排列,合点端大孢子为功能大孢子,胚囊发育为蓼型。     

海桐大、小孢子发育及雌、雄配子体形成的研究

利用常规石蜡制片法研究了海桐大、小孢子发生及雌、雄配子体发育的过程。结果显示:(1)小孢子母细胞减数分裂过程中的胞质分裂为连续型,四分孢子为以四面体形为主,四分孢子后期部分小孢子壁皱缩;(2)花药壁由4层结构组成,由外到内为表皮、药室内壁、中层和绒毡层;(3)海桐具多个胚珠,单珠被,薄珠心,胚珠类型为倒生胚珠。大孢子母细胞减数分裂主要形成线形排列的4个大孢子,还具有少有的十字形排列,功能大孢子位于合点端;(4)胚囊发育属单孢型的蓼型,成熟的雌配子体为四细胞五核胚囊。     

濒危植物红花木莲大孢子发生和雌配子体发育的研究

研究了濒危植物红花木莲（Manglietia insignisBl)的大孢子发生和雌配子体的发育,红花木莲每朵花心皮数为48-73枚,每心皮内胚珠数4-8颗不等,多数是6颗或8颗,胚朱倒生,双珠被,厚珠心,大孢子四分体线形排列,功能大孢子位于合点端,胚囊发育为蓼型。胚珠具珠孔塞,成熟胚囊的卵细胞败育率高达79.1%。这是造成栽培红花木莲结籽率低的主要原因,较低的结籽率影响了红花木莲迁地保护的有效性。     

柴胡大、小孢子发生及雌、雄配子体发育

以柴胡（Bupleurum chinense）为研究对象,运用石蜡切片技术对其大、小孢子发生及雌、雄配子体发育进行了研究。结果表明：柴胡花药具4个药室,花药壁由表皮、药室内壁、中层和绒毡层4层细胞构成,花药壁发育为双子叶型,腺质绒毡层。小孢子母细胞减数分裂的胞质分裂为同时型,产生正四面体型小孢子。成熟花粉三细胞型。胚珠倒生型,单珠被,薄珠心。大孢子母细胞常为一个雌性孢原直接发育而成,大孢子四分体呈线型或T型排列,多数情况为合点端一个大孢子分化为功能大孢子,由功能大孢子发育为蓼型成熟胚囊。在胚囊发育过程中,珠被内表皮细胞特化成珠被绒毡层。同一朵花中,雄蕊先熟,记录了花蕾大小及雌、雄配子体发育的对应关系。     

八角枫大孢子发生和雌配子体发育

八角枫为顶生胎座、倒生胚珠、单珠被。孢原细胞处于珠心表皮之下,直接起大孢子母细胞的功能。珠心表皮细胞平周分裂产生多层珠心周缘细胞,为厚珠心。四分体线行排列,合点端的大孢子发育为蓼型胚囊。开花前,两极核事例成次生核,或不融合仍保留极核状态。反足细胞退化较晚,胚囊合点端具承珠盘。     

华北驼绒藜大小孢子的发生及雌雄配子体发育过程的解剖学研究

运用石蜡切片技术对华北驼绒藜大、小孢子发生及雌、雄配子体的发育进行了研究.结果表明:(1)花药4室,花药壁由表皮、药室内壁、1~2层中层及1层绒毡层组成,药壁发育为基本型,腺质绒毡层,发育后期为二核或三核;(2)四分体胞质分裂为同时型,小孢子四分体多数为四面体型,偶见十字交叉型;(3)成熟花粉2-细胞型,单核小孢子时期存在不同比例的空壳花粉,从0%~80%不等;(4)胚珠倒生,双珠被,厚珠心,大孢子四分体直线型排列,合点端为功能大孢子,蓼型胚囊.     

青阳参的大孢子发生与雌配子体发育

利用常规石蜡制片技术、荧光显微技术、光镜细胞化学技术、电子显微镜技术对青阳参大孢子发生、雌配子体形成过程进行了详细观察。结果显示,青阳参为边缘胎座,胚珠倒生、短珠柄,单珠被,薄珠心型,珠心细胞含有大量的淀粉粒、线粒体和内质网等;大孢子孢原细胞起源于下表皮并直接行使大孢子母细胞的功能;合点端的大孢子分裂形成8-核胚囊;蓼型胚囊;成熟胚囊中有大量淀粉粒;珠孔受精;胚乳在早期发育阶段以游离核形式存在,约在16~32核的阶段细胞壁形成,通常情况下胚乳核的分裂比合子的分裂早,成熟胚乳细胞单核、形状不规则,没有胚乳吸器;胚的发育经过原胚、球型胚和心型胚阶段,茄型;成熟的种子具有种毛,位于珠孔端的珠被表皮细胞是种毛长出的区域,种子中含有大量的脂肪。     

A contribution to the embryology of Desmodium motorium (Houtt.) Merr. (= D. gyrans (L.f.) DC.) (Fabaceae)

Abstract

The anthers are tetrasporangiate. The anther wall comprises epidermis, fibrous endothecium, middle layer and tapetal layer. The tapetum is of the Glandular type and its cells remain uninucleate. Meiosis in pollen mother cells is normal and simultaneous cytokinesis leads to the formation of tetrahedral and decussate microspore tetrads. The pollen grains are shed at 2-celled stage. The ovule is campylotropous, bitegmic and crassinucellate. Meiosis in megaspore mother cell results in the formation of linear or occasionally T-shaped megaspore tetrad. The chalazal megaspore develops into Monosporic Polygonum type of embryo sac. Endosperm development is of the Nuclear type.     

濒危物种灰叶胡杨的大孢子发生和雌配子体发育

用石蜡切片法对濒危物种灰叶胡杨的大孢子发生和雌配子体发育过程进行观察研究.结果显示,灰叶胡杨雌蕊由三心皮构成,侧膜胎座,胚珠为倒生型,有18～21列;发育早期的胚珠为双珠被,厚珠心;当外珠被发育至与内珠被处于同一水平时,内珠被便开始退化,故成熟胚珠为单珠被;孢原细胞1个,并且自表皮下2层处分化;大孢子母细胞由孢原细胞分裂后形成的造孢细胞直接发育而来;大孢子四分体直线形排列,合点端的大孢子为功能大孢子,蓼型胚囊;在胚囊发育过程中珠孔端的珠心组织退化.根据开花物候不同阶段花的形态特征,可以初步判断灰叶胡杨大孢子发生和雌配子体的发育进程.     

狭叶柴胡大小孢子发生和雌雄配子体发育的研究

用石蜡切片法、半薄切片法对狭叶柴胡的大、小孢子发生和雌、雄配子体发育进行观察研究。结果显示:(1)狭叶柴胡花药壁的发育为双子叶型,腺质绒毡层;小孢子母细胞减数分裂过程中的胞质分裂为同时型,四分孢子为正四面体形;成熟的花粉粒为3-细胞型,具3个萌发孔。(2)倒生型胚珠,单珠被,薄珠心;大孢子母细胞常为一个雌性孢原直接发育而成,大孢子四分体呈线型,多数情况为合点端一个大孢子分化为功能大孢子;由功能大孢子发育为蓼型成熟胚囊。(3)八核胚囊时期,珠心基部和两侧的一些珠心细胞留存较久,成为珠心座细胞。此外,珠被内表皮细胞发育为珠被绒毡层。     

Comparative osteology and relationships of the Umbridae (Pisces: Salmoniformes)

The phylogenetic relationships of the five living species of umbrids are examined through a comparative osteological study based on a series of cleared-and-stained specimens of each species. The Umbridae appear to be strictly monophyletic. In addition, for 45 characters, the outgroup Esox shares one character-state with at least one umbrid species, while two or more umbrid species share the other state. Assuming that the states shared with Esox are primitive for the Umbridae, the hypothesis that Dallia is more closely related to Umbra than to Novumbra is supported by compatibility and Wagner-tree analysis of the data. Thirteen derived characters are shared by Dallia and Umbra , 20 more are shared by the three species of Umbra , and four more by U. limi and U. pygmaea. Eight characters are considered likely to have undergone reversal or parallel evolution.