文冠果可孕花与不孕花发育过程的比较研究简

利用半薄切片和透射电镜技术对文冠果可孕花和不孕花的发育过程进行观察和比较。结果显示：(1)小孢子发育初期,两种类型花花药形态无明显差别;小孢子发育双核期,可孕花花药内壁纤维层细胞壁带状加厚,无唇细胞形成。而不孕花花药同侧两个花粉囊之间唇细胞正在分化;小孢子发育成熟期,不孕花花药唇细胞完全形成;散粉期,不孕花花药开裂呈双心形,而可孕花花药则不能开裂散粉。(2)可孕花雌蕊子房内有两室,柱头细胞排列紧密,柱头逐渐发育成圆球形,周围密布乳突细胞,具中空花柱道;不孕花雌蕊柱头停止发育,无中空花柱道,子房室变小,胚囊发育退化。(3)不孕花花药绒毡层中含大量蛋白体,小泡以及乌氏体等细胞器,发育后期绒毡层解体。而可孕花花药绒毡层中细胞器和营养物质积累均较少,发育后期绒毡层解体不完全。(4)可孕花花药内花粉粒细胞壁连续无萌发孔,细胞内含物较少。不孕花花药内花粉出现3个向内凹陷的萌发孔,且花粉内含有大量造粉质体和脂类物质。     

濒危植物羊角槭小孢子发生与雄配子体发育研究

利用常规石蜡切片法对羊角槭的小孢子发生及配子体发育进行了研究,结果表明：羊角槭花分两性花与雄花,两性花花药不散粉,雄花散粉;花药具四个花粉囊,其发育类型为基本型;药室内壁呈纤维状加厚;绒毡层为腺质型;孢质分裂为同时型;小孢子四分体呈四面体形排列;成熟花粉粒为二细胞型。羊角槭花药发育过程中出现严重败育现象,表现为四分体胼胝质提早溶解、单核小孢子彼此粘连、花粉液泡化等,形成干瘪、内陷的花粉,一定程度上影响花粉质量;另初步测得羊角槭的花粉生活力在36.98%~60.54%之间,平均生活力为45.97%。本文将为羊角槭花药发育、小孢子发生和雄配子体发育过程及出现的异常现象提供解剖学资料。     

大叶铁线莲大小孢子发生及雌雄配子体发育

铁线莲属植物在花部形态和结构方面存在较大差异, 遗传背景相对复杂。因此, 在杂交育种前对其进行胚胎学研究具有重要意义。利用石蜡切片技术对大叶铁线莲(Clematis heracleifolia)大小孢子发生及雌雄配子体发育过程进行研究, 结果显示, 大叶铁线莲具雄株和两性花植株。雄花中, 雄配子体发育偶见败育现象; 而两性花中多数花粉发育异常, 形成功能性雌花。正常发育的两性花中, 雄蕊较雌蕊先发育完全。花药4室, 具腺质绒毡层, 偶见变形绒毡层。胞质分裂为同时型, 以四面体型四分体为主, 偶见左右对称型。成熟花药中, 花药壁由纤维状加厚的表皮及药室内壁构成, 花粉粒为2-细胞型, 近球状, 散沟型。子房1室, 内含少量退化胚珠及1个发育正常的胚珠, 倒生, 单珠被, 薄珠心, 蓼型胚囊, 具线形大孢子四分体及双核反足细胞。大叶铁线莲可能处于相对进化的过渡地位。在杂交育种中, 建议以雄花植株作为父本, 两性花植株仅用作母本; 在两性花花芽大小为0.5-0.8 cm时进行去雄处理。     

大叶铁线莲大小孢子发生及雌雄配子体发育

铁线莲属植物在花部形态和结构方面存在较大差异, 遗传背景相对复杂。因此, 在杂交育种前对其进行胚胎学研究具有重要意义。利用石蜡切片技术对大叶铁线莲(Clematis heracleifolia)大小孢子发生及雌雄配子体发育过程进行研究, 结果显示, 大叶铁线莲具雄株和两性花植株。雄花中, 雄配子体发育偶见败育现象; 而两性花中多数花粉发育异常, 形成功能性雌花。正常发育的两性花中, 雄蕊较雌蕊先发育完全。花药4室, 具腺质绒毡层, 偶见变形绒毡层。胞质分裂为同时型, 以四面体型四分体为主, 偶见左右对称型。成熟花药中, 花药壁由纤维状加厚的表皮及药室内壁构成, 花粉粒为2-细胞型, 近球状, 散沟型。子房1室, 内含少量退化胚珠及1个发育正常的胚珠, 倒生, 单珠被, 薄珠心, 蓼型胚囊, 具线形大孢子四分体及双核反足细胞。大叶铁线莲可能处于相对进化的过渡地位。在杂交育种中, 建议以雄花植株作为父本, 两性花植株仅用作母本; 在两性花花芽大小为0.5-0.8 cm时进行去雄处理。     

革苞菊胚胎学研究 Ⅰ.大、小孢子发生和雌、雄配子体发育

革苞菊为雌雄异株。在雄花中 ,花药 4室 ,药壁发育为双子叶型 ,由表皮、药室内壁 ,一层中层和绒毡层组成。绒毡层于小孢子四分体时期开始变形 ,其细胞原生质体向药室中移动 ,为变形绒毡层。小孢子孢原为多细胞 ,小孢子母细胞减数分裂产生四面体型的小孢子四分体。四分体胞质分裂为同时型。成熟花粉 3-细胞型。单核期的小孢子出现壁发育不良和巨大及空花粉现象。在雌花中 ,胚珠是倒生的 ,单珠被 ,薄珠心 ,珠被于孢原期已发育完整。大孢子孢原单细胞。由孢原细胞直接发育形成大孢子母细胞。 4个大孢子直线型 ,蓼型胚囊。于成熟胚囊期观察到发育异常的胚囊。通过对胚囊发育过程中营养物质消长规律的研究 ,讨论了环境与发育的相关性问题。     

Megasporogenesis,Microsporogenesis and Development of Gametophytes in Eleutherococcus senticosus (Araliaceae)

This paper describes megasporogenesis, microsporogenesis, and development of female and male gametophytes in Eleutherococcus senticosus. The main results are as follows: Flowers of E. senticosus are epigynous, pentamerous. Anthers are 4 -microsporangiate. An ovary has 5 loculi. Each ovary loculus has 2 ovules: the upper ovule and the lower ovule. The upper one is orthotropous and degenerates after the formation of archesporial cell, while the lower one is anatropous, unitegmic and crassinucellar, and able to continue developing. In male plants, microsporogenesis and development of male gametophytes took place in regular way, but a series of abnormal phenomena were found in megasporogenesis and development of female gametophytes. The microspore mother cells gave rise to tetrahedral tetrads by meiosis. Cytokinesis was of the simultaneous type. The mature pollen was 3-celled and shed singly. The anther wall formation belonged to the dicotyledonous type. At the stage of microspore mother cell, the anther wall consisted of four layers, i.e. epidermis, endothecium, middle layer, and tapetum. The tapetum was of glandular type and its most cells were binucleate. When microspores were at the uninucleate stage, the tapetum began to degenerate in situ. When microspores developed into 3-celled pollen grains, the tapetum had fully degenerates. In the lower ovule of male flower, the megaspore mother cell gave rise to a linear or “T” -shaped tetrad. In some cases, a new archesporial cell over the tetrad or two tetrads parallel or in a series were observed. Furthermore, the position of functional megaspore was variable; any one or two megaspores might be functional, or one megaspore gave rise to a uninucleate embryo sac, but two other megaspores also had a potentiality of developing into the embryo sac. In generally, on the day when flowers opened, female gametophytes contained only 4 cells: a central cell, two irregular synergids and one unusual egg cell. In female plants, microspore mother cells and secondary sporogenous cells were observed. But at the stage of secondary sporogenous cell, the newly differentiated tapetum took the appearance of degeneration. Later, during the whole stage of meiosis, the trace of degenerative tapetum could be seen. At last, the microsporangium degenerated and no tetrad formed. On the blossom day, all anthers shriveled without pollen grains. In female flowers, megasporogenesis and development of female gametophytes were normal: the tetrad of megaspores was linear or “T”-shaped; the chalazal megaspore was usually functional; the development of embryo sac was of the Polygonum type. On the blossom day, most embryo sacs consisted of 7 cells with 8 nuclei or 7 cells with 7 nuclei; but the egg apparatus was not fully developed. In hermaphroditic plants, microsporogenesis was normal but the development of male gametophytes was partially abnormal. When the hermaphroditic flowers blossomed, there were more or less empty pollen grains in the microsporangium and these pollen grains were quite different in size. The development of most gynoecia was normal but numerous abnormal embryo sacs could be seen. On the blossom day, female gametophytes were mainly 7-celled with 8-nuclei or with 7-nuclei or 4-celled with antipodal cells degenerated; the egg apparatus wasnot fully developed either.     

MORPHOLOGY,VASCULAR ANATOMY AND EMBRYOLOGY OF PISTILLATE AND STAMINATE FLOWERS OF ASPARAGUS OFFICINALIS

Flowers of three pistillate (female), two heterogametic staminate (male) and two homogametic male genotypes of Asparagus officinalis L. were compared for morphology and vascular anatomy of the flower and for embryological development to the stage of mature ovules and pollen. Flowers are liliaceous, the staminate with rudimentary pistils and the pistillate with collapsed anthers. The uncomplicated vascular pattern differs between staminate and pistillate flowers only in the size and degree of maturation of bundles to stamens and carpels. Longer styles appear to be correlated with a greater extent of ovule development in ovaries of staminate flowers. Microsporogenesis in males is normal with wall development corresponding to the Monocotyledonous type. The tapetum is glandular and binucleate, cytokinesis successive, the tetrads isobilateral or occasionally decussate, and the mature pollen grain two-celled. A pair of heteromorphic, possibly sex, chromosomes was observed in heterogametic male plants. Anther development is initially the same in pistillate flowers, but the tapetum degenerates precociously followed by collapse of microspore mother cells. In pistillate flowers the ovules are hemitropous, bitegmic, and slightly crassinucellate. Megasporogenesis-megagametogenesis conforms to the Polygonum type. In staminate flowers ovule development is like that in pistillate flowers until degeneration starts in nucellar and integumentary cells at the chalazal end. Ovules in both homogametic male genotypes rarely complete meiosis, while in the heterogametic males it is normally completed with about one ovule in 20 flowers forming a mature megagametophyte. Since manipulation of sex expression in Asparagus could be important in developing inbred male and female lines for breeding purposes, those aspects of the morphological and embryological observations presented which might be useful in planning experiments to induce sex changes are discussed briefly.     

开口箭大小孢子发生及雌雄配子体发育

利用石蜡切片技术,对百合科植物开口箭(Tupistra chinensis Baker)大小孢子发生及雌雄配子体发育进程进行胚胎学观察分析,以明确开口箭胚胎发育的特征,为百合科植物的研究提供生殖生物学依据。结果表明:(1)开口箭花药具有4个药室,花药壁的发育方式为基本型,由表皮、药室内壁、中层及绒毡层组成;绒毡层发育类型为分泌型,到四分体花药阶段绒毡层细胞开始解体退化,花药成熟时完全消失。(2)花粉母细胞减数分裂为连续型,依次形成二分体、四分体,四分体为左右对称形;成熟花粉为2-细胞花粉,具单萌发沟。(3)子房3室,倒生型胚珠6枚,双珠被,薄珠心;在花部的分化早期,由珠心顶端表皮下方分化出雌性孢原细胞,孢原细胞经过一次平周分裂形成周缘细胞和造孢细胞,造孢细胞发育为大孢子母细胞;大孢子母细胞第一次减数分裂后形成二分体,珠孔端的二分体孢子退化,合点端的二分体孢子继续第二次分裂,形成两个子细胞依次发育为二核胚囊、四核胚囊和八核胚囊;开口箭的胚囊发育类型为葱型。     

甜荞pin型花与thrum型花雌雄蕊发育的比较研究

为从形态上研究甜荞(Fagopyrum esculentum)二型花发育的差异性,该文运用石蜡切片技术对甜荞pin型花和thrum型花大、小孢子发生和雌、雄配子体的发育过程进行观察比较.结果表明:(1)甜荞2种花的雌蕊、雄蕊发育的细胞学特征有很高的相似性,具直生胚珠、双珠被、厚珠心;大孢子四分体直线型排列,合点端为功能...     

Anther structure and pollen development in Melicoccus lepidopetalus (Sapindaceae): An evolutionary approach to dioecy in the family

Anther and pollen development in staminate and pistillate flowers of dioecious Melicoccus lepidopetalus (Sapindaceae) were examined by light and electron microscopy. Young anthers are similar in both types of flowers; they consist of epidermis, endothecium, two to four middle layers and a secretory tapetum. The microspore tetrads are tetrahedral. The mature anther in staminate flowers presents compressed epidermal cells and endothecium cells with fibrillar thickenings. A single locule is formed in the theca by dissolution of the septum and pollen grains are shed at two-celled stage. The mature anthers of pistillate flowers differ anatomically from those of staminate flowers. The epidermis is not compressed, the endothecium does not develop fibrillar thickenings, middle layers and tapetum are generally persisting, and the stomium is nonfunctional. Microspore degeneration begins after meiosis of microspore mother cells. At anthesis, uninucleate microspores and pollen grains with vegetative and generative nuclei with no cytokinesis are observed. Some pollen walls display an abnormal exine deposition, whereas others show a well formed exine, although both are devoid of intine. These results suggest that in the evolution towards unisexuality, the developmental differences of anther wall tissues and pollen grains between pistillate and staminate flowers might become more pronounced in a derived condition, such as dioecy.     

Formation of microspores and development of male gametes in Paeonia jishanensis,with an analysis of factors of endangerment of this entity

Investigated in the present work were development of microspores and formation Of male gametes in Paeonia jishanensis T．Hong et W．Z．Zhao)．Its anthers are 4-sporran giate;structure of anther wall is of the Dicotyledonous type,with glandular tapetum;cy tokinesis at meiosis of microspore mother cells is simultaneous;tetrads are mostly tetrahe dral,less frequently isobilateral,and mature pollen grains are 2-celled． The overall observa tion on formation of microspores and development of male gametes made in this work is the first for woody peonies．In addition,we observed in the present work abnormal phenomena at meiosis of microspore mother cells and uninucleate microspores,and also made measure ments of fertility of pollen grains．The results show that their fertility ranges from 45.0％ to 84.2％ and varies among flowers,among anthers in a flower and among microsporangia in an anther． The abnormal processes found in development of male gametes are not considered as an important factor responsible for the endangerment of the species．     

湖北黄精大小孢子发生及雌雄配子体发育

【目的】研究湖北黄精花部形态结构特征和大小孢子发生及雌雄配子体发育过程,以丰富黄精属植物的生殖生物学理论,为进一步开展湖北黄精的品种选育提供依据。【方法】以不同发育时期的湖北黄精花芽为试验材料,用显微观察法观察花部形态结构特征,石蜡切片技术对单花雌雄蕊进行切片观察。【结果】湖北黄精的花被为白色或淡黄绿色,花被筒近喉部稍缢缩;具6枚雄蕊,花丝下端与花被合生,花药开裂方式为纵裂;雌蕊子房上位,3心皮,花柱与子房等长。湖北黄精花药壁由4层细胞组成,成熟的绒毡层具多核,绒毡层发育类型为分泌型;小孢子母细胞减数分裂为连续型,四分体呈左右对称型排列,成熟花粉粒为2-细胞型;存在小孢子发育不同步的现象。雌蕊胚珠具双珠被、厚珠心;四分体呈直线型排列,胚囊发育类型为蓼型;存在双胚囊胚珠现象。在雄蕊的花药壁和雌蕊的子房壁都观察到有束状草酸钙针晶。【结论】湖北黄精雌雄蕊具有较原始的发育特征,虽然在发育过程中都存在异常现象,但雄蕊最终能形成正常的雄配子体,雌蕊低频率的双胚囊现象对总体受精结果影响很小。湖北黄精杂交育种可以选择花药开裂前一时期的花粉,花药壁和子房壁观察到的束状草酸钙针晶无法作为湖北黄精物种鉴定的...     

长花柱型滇丁香小孢子发生及雄配子体发育

利用常规石蜡切片法和细胞学压片法,对异型花柱植物滇丁香的长花柱型植株的小孢子发生、雄配子体发育及花粉萌发进行观察。结果表明:(1)长花柱型滇丁香具5枚花药,花药4室。(2)花药壁由1层表皮、1层花药内壁、2层中层和1~3层绒毡层组成;花药壁发育方式为基本型,绒毡层类型为腺质绒毡层。(3)小孢子母细胞减数分裂的胞质分裂为同时型,四分体排列方式为四面体型,偶有左右对称型;不同药室间小孢子母细胞减数分裂不同步。(4)成熟花粉粒为二细胞型。(5)小孢子发生和雄配子体发育过程正常,表明长花柱型滇丁香属于发育正常的两性花。(6)授粉4h后,长花柱型滇丁香的花粉在长、短两种花柱柱头上的萌发率分别达(91.8±1.6)%和(93.2±1.1)%,且两者间无显著性差异(t=1.585,df=8,p=0.152),表明长花柱型滇丁香的成熟花粉粒在长、短两种花柱柱头上的萌发均正常。     

落葵的花粉粒和胚囊的形成与发育

落葵(Basella rubra L.)小孢子的发育为同时型,四分体呈四面体排列。在花粉母细胞减数分裂过程中,可清楚地看到胼胝壁的消长变化。三胞花粉,具散沟和网状纹饰。腺质绒毡层。 胚囊的发育为蓼型。反足细胞早期退化。内珠被突出形成珠被喙,同时,在其珠孔区域,有由内珠被的内表皮细胞所发育而来的类似盖状结构。 本文还注意到同一花中以及相邻花朵之间,花粉粒与胚囊发育进程的相关。花粉粒的发育略早于胚囊的发育,但以后由于胚囊母细胞形成胚囊的进程较为迅速,以致花粉粒与胚囊能够同时成熟。     

Reproductive morphology of Sargentodoxa cuneata (Lardizabalaceae) and its systematic implications

The reproductive morphology of Sargentodoxa cuneata (Oliv) Rehd. et Wils. is investigated through field, herbarium, and laboratory observations. Sargentodoxa may be either dioecious or monoecious. The functionally unisexual flowers are morphologically bisexual, at least developmentally. The anther is tetrasporangiate, and its wall, of which the development follows the basic type, is composed of an epidermis, endothecium, two middle layers, and a tapetum. The tapetum is of the glandular type. Microspore cytokinesis is simultaneous, and the microspore tetrads are tetrahedral. Pollen grains are two-celled when shed. The mature ovule is crassinucellate and bitegmic, and the micropyle is formed only by the inner integument. Megasporocytes undergo meiosis resulting in the formation of four megaspores in a linear tetrad. The functional megaspore develops into an eight-nucleate embryo sac after three rounds of mitosis. The mature embryo sac consists of an egg apparatus (an egg and two synergids), a central cell, and three antipodal cells. The pattern of the embryo sac development follows a monosporic Polygonum type. Comparisons with allied groups show that Sargentodoxa shares more synapomorphies with the Lardizabalaceae than other Ranunculales. Characteristics of its reproductive morphology are consistent with the placement of Sargentodoxa as the sister group of the remaining Lardizabalaceae. It does not possess a sufficient number of apomorphic characters to justify its separation into a separate family or subfamily. It is best retained as a member of the Lardizabalaceae.     

车桑子小孢子发生与雄配子体发育

为了解干热河谷区车桑子(Dodonaea viscosa)胚胎学特征及其结籽率低的原因,采用常规石蜡切片法和电镜扫描技术对车桑子小孢子发生、雄配子体发育和花粉的形态特征进行了观察。结果表明,车桑子花药具有4个花粉囊。完整的花药壁从外到内依次为表皮、药室内壁、2～3层中层细胞和绒毡层;绒毡层类型是腺质绒毡层。花药成熟期,中层、绒毡层均退化消失。小孢子母细胞进行同时型胞质分裂;四分体为四面体型结构。成熟的花粉为二细胞型。花粉近球形,外壁密布颗粒状纹饰,具有3条不构成合沟的萌发沟。雄性生殖发育过程出现的异常现象可能是干热河谷地区车桑子结籽率低的原因之一。     

An Arabidopsis F-box protein regulates tapetum degeneration and pollen maturation during anther development

The Arabidopsis anther has a bilateral symmetry with four lobes, each consisting of four distinct layers of somatic cells from the outer to inner side: epidermis, endothecium, middle layer and tapetum. The tapetum is a layer of cells comprising the inner surface of the pollen wall. It plays an important role in anther development by providing enzymes, materials and nutrients required for pollen maturation. Genes and molecular mechanisms underlying tapetum formation and pollen wall biosynthesis have been studied in Arabidopsis. However, tapetum degeneration and anther dehiscence have not been well characterized at the molecular level. Here, we report that an Arabidopsis gene, designated reduced male fertility (RMF), regulates degeneration of tapetum and middle layer during anther development. The Arabidopsis dominant mutant rmf-1D overexpressing the RMF gene exhibited pleiotropic phenotypes, including dwarfed growth with small, dark-green leaves and low male fertility. Tapetum development and subsequent degeneration were impaired in the mutant. Accordingly, pollen maturation was disturbed, reducing the male fertility. In contrast, tapetum degeneration was somewhat accelerated in the RMF RNAi plants. The RMF gene was expressed predominantly in the anther, particularly in the pollen grains. Notably, the RMF protein contains an F-box motif and is localized to the nucleus. It physically interacts with the Arabidopsis-Skp1-like1 protein via the F-box motif. These observations indicate that the RMF gene encodes an F-box protein functioning in tapetum degeneration during anther development.     

星星草大、小孢子发生与雌、雄配子体发育的观察

利用常规石蜡制片法研究了星星草[Puccinellia tenutiflora(Griseb．)Scribn．et Merr．]大、小孢子发生及其雌、雄配子体的发育过程。主要结论是：(1)小孢子母细胞减数分裂过程中的胞质分裂为连续型,四分孢子为左右对称型;(2)成熟的花粉为三细胞型,具单萌发孔;(3)花药壁由4层结构组成,最外层为表皮,其内分别为药室内壁、中层、绒毡层,绒毡层为分泌型,花药壁的发育属于单子叶型;(4)星星草为单子房,单胚珠,双珠被,薄珠心,倒生型胚珠。大孢子母细胞经减数分裂形成线形排列的4个大孢子,合点端大孢子具功能;(5)胚囊发育属于蓼型,成熟胚囊形成时,反足细胞经无丝分裂形成4～6个反足细胞,反足细胞内可能存在多次DNA复制过程。