黄顶菊的大孢子发生、雌配子体与胚胎发育

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...     

沙田柚雌雄蕊发育及其相关性研究

沙田柚为例生胚珠,双珠被,厚珠心,具多个孢原细胞,其中之一发育形成大孢子母细胞,四个大孢子呈直线形排列,功能大孢子居合点端,胚囊发育为蓼型,珠孔端有珠心冠。 花药为四分孢子囊,小孢子母细胞减数分裂过程中,胞质分裂为同时型,四分小孢子四面体型,成熟花粉粒为二细胞型。 同一朵花中,雌雄蕊发育的相关性是:当大孢子母细胞形成时,小孢子进入单核期。当雌蕊发育进入大孢子时期,双核花粉粒形成。大孢子和双核花粉粒都在开花前10天左右形成,雌雄蕊同时成熟。     

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。     

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。     

八角莲大孢子发生和雌配子体形成

首次报道了八角莲(Dysosma versipellis (Hance)M.cheng)大孢子发生和雌配子体形成的过程.结果:双珠被,多为厚珠心胚珠,少数为假厚珠心,胚珠多为横生,少数为弯生;边缘胎座,子房一室,多胚珠,珠孔由两层珠被共同形成,呈"之"字形;多为单孢原,位于珠心表皮下:偶见2～3个孢原细胞位于珠心表皮下;大孢子母细胞有两种发生方式;直线形大孢子四分体,合点端的大孢子发育为功能大孢子,蓼型胚囊;成熟胚囊中,二个极核在受精前合并为次生核;三个反足细胞不发达,较早退化;"品"字形卵器极性明显,其中卵细胞与助细胞极性相反;助细胞发达,其丝状器在不同发育时期形态及大小不同,且具吸器功能.     

茶的胚囊发育及超微结构研究

茶的胚囊发育及超微结构研究严学成（华南农业大学生物系,广州５１０６４２）（－）胚囊的发育茶（ＣａｍｅＩＩｉａＳｉｎｅｎｓｉｓ）的胚囊发育起始于珠心顶端一层表皮的薄珠心下一个体积较大,细胞质浓的孢原细胞,它起着大孢子母细胞作用,进行减数分裂形成二分体,...     

粉叶小檗大孢子发生和雌配子体形成

采用石蜡切片方法对粉叶小檗（Berberis pruinosa Franch.)的大孢子发生和雌配子体形成过程进行了研究。主要结果如下：雌蕊1枚,子房单心皮,边缘胎座,2枚胚珠倒生,具双珠被,厚珠心,珠孔由内外两层珠被共同形成,呈“Z”字形;单孢原,位于珠心表皮下;直线形大孢子四分体,合点端的1个大孢子发育为功能大孢子,胚囊发育类型为蓼型;成熟胚囊中,2个极核在受精前融合为次生核;3个反足细胞不发达,较早退化;"品"字形卵器,其中助细胞发达且具丝状器。     

濒危植物马蹄参的大孢子发生和雌配子体发育

为探讨马蹄参(Diplopanax stachyanthus Hand.-Mazz.)濒危机制与雌性生殖发育的关系,采用石蜡切片法观察马蹄参大孢子形成和雌配子体的发育过程。结果表明,马蹄参雌蕊单心皮,子房下位,1室,1枚胚珠。胚珠横生于短片状胎座上,具单珠被,厚珠心。单孢原细胞自珠心1~2层表皮细胞处分化;大孢子四分体为直线形。成熟胚囊中,2个极核在受精前融合为次生核,3个反足细胞不发达,较早退化;二核胚囊时期出现二核分裂不均且较小核退化消失的异常发育现象。因此,马蹄参雌配子体发育过程中出现异常现象是造成其结实率低的主要原因。     

秦艽的胚胎学研究

秦艽具５个雄蕊,花药壁的发育属于双子叶型,为变形绒毡尾,花粉母细胞减粉分裂时的胞质分裂为同时型,四分孢子主要呈四面体型,成熟花粉粒球形,具３－孔沟,多为２细胞。子房一定,中轴胎座,其上着生众多具单珠被,薄珠心的倒生胚珠,大孢子母细胞减数分裂形成线型四分体。合点端大孢子继续发育,少数为合点端第二个大孢子形成功能大孢子,胚囊发育属蓼型,受精作用属于有丝分裂前配子融合类型,胚按茄型发育,胚乳核型,胚乳早     

红皮树胚胎发育

本文报道红皮树(Styrax suberifoltus Hook.et Arn.)大小孢子发育和早期胚胎发生。子房具胚珠20—23枚,胚珠横生,珠被二层,薄珠心,孢原细胞直接起大孢子母细胞作用。合点端大孢子具功能。胚囊发育为正常型。成熟胚囊具大量淀粉粒。小孢子形成为同时型,成熟花粉为二细胞型。传粉后、受精前两个助细胞在形状和对苏木精着色程度上有显著区别。胚乳发育为细胞型。在合子分裂前,胚乳细胞增至约26个时,暂时停止分裂。苏木精对细胞质不易着色,似解体细胞。有胚乳吸器。     

A pattern of unique embryogenesis occurring via apomixis in Carya cathayensis

Apomixis represents an alteration of classical sexual plant reproduction to produce seeds that have essentially clonal embryos. In this report, hickory (Carya cathayensis Sarg.), which is an important oil tree, is identified as a new apomictic species. The ovary has a chamber containing one ovule that is unitegmic and orthotropous. Embryological investigations indicated that the developmental pattern of embryo sac formation is typical polygonum-type. Zygote embryos were not found during numerous histological investigations, and the embryo originated from nucellar cells. Nucellar embryo initials were found both at the micropylar and chalazal ends of the embryo sac, but the mature embryo developed only at the nucellar beak region. The mass of the nucellar embryo initial at the nucellar beak region developed into a nucellar embryo or split into two nucellar proembryos. The later development of the nucellar embryo was similar to the zygotic embryo and progressed from globular embryo to heart-shape embryo and to cotyledon embryo.     

Double Whole Mount in situ Hybridization of Early Chick Embryos

The chick embryo is a valuable tool in the study of early embryonic development. Its transparency, accessibility and ease of manipulation, make it an ideal tool for studying gene expression in brain, neural tube, somite and heart primordia formation. This video demonstrates the different steps in 2-color whole mount in situ hybridization; First, the embryo is dissected from the egg and fixed in paraformaldehyde. Second, the embryo is processed for prehybridization. The embryo is then hybridized with two different probes, one coupled to DIG, and one coupled to FITC. Following overnight hybridization, the embryo is incubated with DIG coupled antibody. Color reaction for DIG substrate is performed, and the region of interest appears blue. The embryo is then incubated with FITC coupled antibody. The embryo is processed for color reaction with FITC, and the region of interest appears red. Finally, the embryo is fixed and processed for phtograph and sectioning. A troubleshooting guide is also presented.     

草地早熟禾胚胎学研究 Ⅲ．多胚囊及多胚现象

报道了草地早熟禾中多胚囊的起源、发育和结构。在１个胚珠中,大孢子母细胞周围可以有一到多个起源于珠心细胞的胚囊原始细胞,并可以发育成为多胚囊,其中具有两个胚囊的可以发育成为成熟胚囊。起源于珠心的体细胞无孢子生殖胚囊的发育属于山柳菊型。两个成熟胚囊中,都可以形成胚和胚乳,因而形成了具假多胚的种子。位于中部的胚来源于珠心还囊,属于无融合生殖形成的胚。两个以上的多胚囊不能形成成熟胚囊。     

IVF-ET时影响胚胎着床率的因素分析

胚胎移植成功的标志性事件是胚胎着床。着床是一个高度协调的事件,影响胚胎着床的因素主要有胚胎质量和子宫内膜容受性两方面。     

漆树胚,胚乳发育及花果生长的相关性研究

漆树为倒生胚珠,双珠被,厚珠心,具承珠盘及拟珠孔塞,胚囊发育为蓼型,核型胚乳,胚发育为柳叶菜型,后历经棒状形胚、心形胚、鱼雷形胚和成熟胚各期。花和果实生长与胚及胚乳发育有密切的相关性,胚内具原始的乳汁道系统为重要特征。一些胚珠内无胚或胚乳早期退化引起胚败育是造成种子空籽原因之一。     

哺乳动物滋养层细胞在胚胎植入中的作用

胚胎植入是哺乳动物生殖的关键环节,是一个非常复杂的过程.在胚胎植入过程中,多种着床相关因子、激素在母体-胚胎之间进行多重作用,引发复杂的生理作用,从而完成胚胎着床.在母体-胚胎界面上,胎源性滋养层细胞与母体子宫内膜细胞在信号联系（妊娠识别）和组织紧密连接（胚胎植入）过程中起着决定性作用,尤其是胚源性滋养层细胞,在胚胎植入过程中起主导作用.本文通过对滋养层细胞在胚胎植入中的作用的阐述,为进一步阐明胚胎植入的分子机制提供思路.     

大叶杨配囊及胚珠的形成和发育

本文应用细胞化学方法研究了大叶杨胚珠、胚囊的形成和发育过程中核酸、蛋白质及不溶性多糖的分布和消长。大孢子母细胞、大孢子四分体及功能大孢子中含较少不溶性多糖,但却含丰富的RNA和蛋白质。功能大孢子经分裂发育成八核的蓼型胚囊。四核胚囊开始积累细胞质多糖,成熟胚囊中除反足细胞外充满淀粉粒。反足细胞形成后不久即退化。助细胞具多糖性质的丝状器,受精前两个助细胞退化。卵细胞核对Feulgen反应呈负反应。二极核受精前由胚囊中部移向卵器,与卵器接触后融合形成次生核。发育早期的胚珠为厚珠心,双珠被。晚期,内珠被退化,故成熟胚珠为单珠被。四核胚囊时期,珠孔端珠心组织退化,胚囊伸向珠孔形成胚囊喙。合点端珠心组织含丰富的蛋白质和核酸,这一性质与绒毡层性质相似,可能涉及胚囊的营养运输。胚囊的营养来源于子房和胎座细胞内贮存的淀粉粒。     

Sequential steps for developmental arrest in Arabidopsis seeds

The continuous growth of the plant embryo is interrupted during the seed maturation processes which results in a dormant seed. The embryo continues development after germination when it grows into a seedling. The embryo growth phase starts after morphogenesis and ends when the embryo fills the seed sac. Very little is known about the processes regulating this phase. We describe mutants that affect embryo growth in two sequential developmental stages. Firstly, embryo growth arrest is regulated by the FUS3/LEC type genes, as mutations in these genes cause a continuation of growth in immature embryos. Secondly, a later stage of embryo dormancy is regulated by ABI3 and abscisic acid; abi3 and aba1 mutants exhibit premature germination only after embryos mature. Mutations affecting both developmental stages result in an additive phenotype and double mutants are highly viviparous. Embryo growth arrest is regulated by cell division activities in both the embryo and the endosperm, which are gradually switched off at the mature embryo stage. In the fus3/lec mutants, however, cell division in both the embryo and endosperm is not arrested, but rather is prolonged throughout seed maturation. Furthermore ectopic cell division occurs in seedlings. Our results indicate that seed dormancy is secured via at least two sequential developmental processes: embryo growth arrest, which is regulated by cell division and embryo dormancy.     

北柴胡胚和胚乳的发育及对其种子萌发的影响

利用常规石蜡制片技术对北柴胡胚和胚乳的发育及对其种子萌发的影响进行了观察。结果表明北柴胡胚的发育属于茄型,基细胞进行一次横分裂后不再分裂,因而胚柄不发达,且很早解体。胚乳的发育属于核型,初生胚孔核的分裂远远早于受精卵的分裂。对果实采收时期胚发育状况进行统计发现,在被测采收期果实中有20％的果实的胚处于球形胚阶段,70％处于心形胚,只有10％处于鱼雷胚,说明北柴胡种子采收时胚处于不同的发育阶段,存在形态后熟现象,这是北柴胡种子萌发难、萌发率低且出苗不整齐的主要因素。     

小麦×大麦胚胎发育的研究——Ⅲ.小麦×大麦胎胚发育过程中淀粉的积累和动态

我们观察了小麦与大麦杂交胚胎发育过程中,雌蕊各个组成部分发生的淀粉积累和转移的动态。结果如下: 1.胚乳和杂种胚早期发育过程中,子房壁和胚囊中淀粉的积累和动态的趋势与其他学者所作小麦自交的情况基本相同。2.当胚乳细胞充满胚囊而胚没有分化时,子房壁中的淀粉已极少,当胚乳解体时,子房壁中淀粉已几乎消失。可见,子房壁中淀粉的迅速消失与胚乳的迅速败育是平行的。3.胚囊发育的停滞与败育跟子房壁组织中淀粉的积累及对胚囊营养的正常供应有密切关系。4.花柱、珠被、珠心组织及胚囊中的助细胞和反足细胞,在整个杂种胚和胚乳发育过程中,始终不存在淀粉粒。助细胞胚亦和助细胞一样,无淀粉粒的存在。