白菜核雄性不育两用系可育和不育花药ATPase的分布

对白菜核雄性不育两用系可育花药和不育花药的ATPase做了定位分析。可育花药的花粉母细胞核中积累了大量的ATPase反应颗粒,而细胞质中ATPase反应颗粒较少,但在线粒体中特异地聚集了一些大的ATPase反应颗粒。减数分裂后,小孢子细胞质中ATPase反应颗粒明显增加。随着小孢子发育,其细胞质中ATPase反应颗粒逐渐减少,但在线粒体中又特异性地聚集了较多的AT-Pase反应颗粒。当花药发育到二胞花粉时期,花粉和绒毡层细胞中的ATPase反应颗粒已很少了。不育花药的花粉母细胞中呈现较多的ATPase,然而在线粒体中很少。异常四分体小孢子细胞质中虽然有较多的ATPase反应颗粒,但还是通过细胞质收缩和质壁分离方式退化。对可育花药的花粉母细胞线粒体中特异出现的簇状ATPase分布现象进行了分析,讨论了不育花药中花粉母细胞线粒体ATPase的异常与花粉败育的可能关系。     

枸杞花药发育过程中钙的分布

在枸杞花药发育过程中,用焦锑酸钾沉淀的钙颗粒显示出了一个与花药发育事件有关的分布特征：在孢原细胞时期的花药中钙颗粒很少。在造孢细胞到小孢子母细胞时期,花药中钙颗粒增加。当花粉母细胞进行减数分裂时,花药中的钙颗粒进一步增加,尤其是在小孢子母细胞的胼胝质壁中。在小孢子发育早期,花药药隔部位的绒毡层细胞质中钙颗粒也明显增加并特异性地分布在其内切向壁上。当小孢子被释放出后,钙颗粒开始特异性积累在正在形成的花粉外壁中,尤其在萌发孔的部位聚集了大量的钙颗粒。当小孢子形成大液泡时,其细胞质中的钙颗粒明显减少。在小孢子分裂形成二胞花粉后,在二胞花粉的大液泡中又特异性地出现许多细小钙颗粒。随着二胞花粉的大液泡完全消失,其细胞质中又出现了许多钙颗粒。接近开花时的成熟花粉粒细胞质中,细小的钙颗粒主要分布在营养细胞和生殖细胞中。枸杞花药发育过程中钙的分布特征反映了其参与调控花粉发育过程。     

水芹花药发育中Ca~(2+)分布特征研究

应用焦锑酸钾沉淀技术对水芹发育花药中的Ca~(2+)分布特征和生理功能进行分析。在小孢子母细胞的胼胝质壁中聚集了较多的钙沉淀颗粒,其他部位较少。小孢子母细胞减数分裂后,花药药壁和药隔组织中的钙沉淀颗粒明显增加。早期小孢子先在花粉外壁基柱层中聚集了较多的钙沉淀颗粒,在小孢子质膜与花粉外壁之间也特异性聚集了许多钙沉淀颗粒。在小孢子形成大液泡过程中,小孢子质膜内陷形成小液泡,钙沉淀颗粒被包裹到小液泡中,并被转移到大液泡中,显示Ca~(2+)参与了液泡的构建。小孢子不等分裂后,二胞花粉中的大液泡分解,细胞质内含物增加,积累营养储存物——淀粉和脂滴。花粉中的钙沉淀颗粒明显减少,而药壁的表皮和药室内壁细胞中的则增加。成熟花粉中钙沉淀颗粒很少,但在花粉外壁的基柱层空隙中仍有许多钙沉淀颗粒分布。水芹花粉中的Ca~(2+)分布的特点显示其在小孢子发育的液泡代谢过程具有重要的生理功能。     

水稻花药发育过程中腺苷三磷酸酶的分布

水稻花粉母细胞中的ATP酶反应颗粒很少,主要分布在细胞核中。组成花药药壁的4层细胞中只有绒毡层细胞核中有较多的ATP酶。减数分裂后,绒毡层细胞质中分化出许多内质网片层,但ATP酶反应颗粒仍很少,其它3层药壁细胞中质膜ATP酶明显增加。在花粉内、外壁中形成了大量的ATP酶反应颗粒,但花粉外壁在小孢子时期形成,ATP酶反应颗粒来自绒毡层细胞的鸟氏体。花粉内壁在二胞花粉时期形成,其中的ATP酶反应颗粒来自花粉营养细胞。二胞花粉的营养细胞比生殖细胞含有更多的ATP酶反应颗粒。     

金线莲花药发育中的钙离子分布特征

该研究以金线莲不同发育时期的花药为材料,采用电子显微镜观察花粉块中的钙离子分布,以揭示钙离子在金线莲花药发育中的相关生理功能。结果发现:(1)在造孢细胞时期,较多的钙沉淀颗粒出现在花药表皮和药室内壁细胞的液泡中,暗示钙离子与植物细胞的液泡发生和形成有关。(2)在减数分裂前期,小孢子母细胞核中聚集了较多的钙沉淀颗粒,当小孢子母细胞分裂时,在二组染色体之间有大量的钙沉淀颗粒,显示钙离子与细胞分裂有关。(3)在合成淀粉的质体表面覆盖了较多的钙沉淀颗粒,显示钙离子与质体中的糖代谢有关。研究表明,开花时在花粉块表面的花粉外壁上和成熟花粉中仍保持有大量的钙沉淀颗粒,为花粉萌发所需钙离子做好了储备。     

玉竹雄配子的发育——着重阐明质体在生殖细胞和营养细胞中的分布和变化

玉竹(Polygonatum simizui Kitag)小孢子在分裂前,质体极性分布导致分裂后形成的生殖细胞不含质体,而营养细胞包含了小孢子中全部的质体。生殖细胞发育至成熟花粉时期,及在花粉管中分裂形成的两个精细胞中始终不含质体。虽然生殖细胞和精细胞中都存在线粒体,但细胞质中无DNA类核。玉竹雄性质体的遗传为单亲母本型。在雄配子体发育过程中,营养细胞中的质体发生明显的变化。在早期的营养细胞质中,造粉质体增殖和活跃地合成淀粉。后期,脂体增加而造粉质体消失。接近成熟时花粉富含油滴。对百合科的不同属植物质体被排除的机理及花粉中贮藏的淀粉与脂体的转变进行了讨论。     

芍药雄配子体发育的超微结构研究

用透射电镜对芍药（Paeonia lactiflora Pall)雄配子体发育进行了研究。结果表明,芍药的小孢子母细胞在减数分裂末期Ⅰ时不形成细胞板,在减数分裂前期Ⅱ形成细胞器带,胞质分裂为同时型,生殖细胞刚形成时有呈PAS正反应的拱形壁,当生殖细胞还未完全脱离花粉内壁时,质膜间的壁物质消失,营养细胞中的脂体沿双质膜规律分布形成一单行的脂体带,在二胞花粉晚期,脂体带包围生殖细胞,形成脂体冠,花粉成熟时,包围生殖细胞的脂体消失,生殖细胞与营养核贴近,构成雄性生殖单位,成熟花粉为二细胞型。     

猕猴桃花粉发育过程中营养物质的积累及转化的研究

猕猴桃花粉发育过程中营养物质的积累及转化的研究袁宗飞,刘晓锋,高霞丽（徐州师范学院生物系,徐州２２１００９）在被子植物小孢子向成熟的雄配子体发育过程中,发生两次有丝分裂,第一次分裂产生一个大的营养细胞和一个小的生殖细胞。营养细胞在发育到一定时期开始积...     

甜菜无融合生殖单体附加系M14花粉发生与发育的超微结构研究

运用透射电子显微镜技术,对甜菜无融合生殖单体附加系M14的小孢子发生、雄配子体发育以及相应的花药壁发育过程进行超微结构的观察研究,以阐明甜菜无融合生殖单体附加系M14花粉发生与发育超微结构特点以及花粉败育的时期和败育的细胞学特征.结果显示:(1)小孢子母细胞减数分裂正常,分裂期间细胞质具有明显的"细胞质改组"现象,主要表现在核糖体减少,质体、线粒体的结构发生规律性的变化,有利于孢子体向配子体的转变.M14减数分裂的胞质分裂为同时型,前期Ⅱ和中期Ⅱ形成"细胞器带";正常发育的花粉,小孢子分裂形成营养细胞和生殖细胞;生殖细胞脱离花粉壁,生殖细胞游离于营养细胞的细胞质中,最初具细胞壁,而后消失,且生殖细胞壁成分与花粉内壁成分相似.(2)三细胞型的成熟花粉含有一个营养细胞和两个具有尾突的精子;每个精子通过两层质膜与营养细胞隔开,含有一个大的精核,长尾突内含少量的细胞质以及纤丝状结构.(3)生殖细胞和精子中缺乏质体.(4)花粉的败育起始于小孢子,大部分受阻于单核-二细胞花粉期,其败育特征为花粉内液泡吞噬作用导致细胞器解体,绒毡层细胞过早解体或肥大生长致使营养供应受阻,可能是导致单核-二细胞花粉败育的主要细胞学原因.研究表明,白花甜菜第九号染色体的附加可能是导致M14大量花粉败育的遗传学因素.     

杜仲花粉不对称分裂的超微结构观察

运用透射电镜对杜仲花粉发育进程进行了观察研究。结果显示,杜仲小孢子的第一次分裂为不等分裂,形成小的生殖细胞和大的营养细胞。分裂开始前小孢子的营养极形成许多小液泡,建立细胞极性;然后随着核膜的解体核周围的细胞器逐渐向纺锤体区靠近,围绕在纺锤体周围。花粉第一次有丝分裂完成后,生殖细胞所获得的细胞器开始分布在细胞的两侧,后来移向生殖细胞的营养极,而紧贴花粉壁的生殖极无细胞器分布。这种生殖细胞早期的细胞极性,可能为进一步分裂形成精细胞奠定基础。     

洋葱花粉发育过程中ATP酶的分布特征(简报)

在真核细胞中,除了线粒体和叶绿体ATPase的功能是合成ATP外,其余部位ATPase是水解ATP以获取生物能量的代谢酶,在生物体细胞内广泛存在。探索ATPase在细胞中的分布状态是研究细胞生理状态的一种重要手段。ATPase在细胞中的多少可反映出细胞当时的生活状态,这一特征已被初步用于探索小麦和水稻雄性不育的细胞生物学研究中,希望通过比较可育花药和不育花药中ATPase的分布差异寻找雄性不育的机理,发现     

FINE-STRUCTURAL STUDY ON THE FORMATION OF THE GENERATIVE CELL WALL AND INTINE-3 LAYER IN A GROWING POLLEN GRAIN OF LILIUM LONGIFLORUM

At the end of mitosis in the lily pollen microspore, the fan-shaped cell plate gives rise to a cell wall delineating a hemispherical cell. At first, the cell wall of the newly formed generative cell and the intine-3 layer of the pollen grain wall are inseparable. Gradually, the wall of the generative cell near the pollen grain wall becomes thicker and wall segments are formed between the thickened zones, and these make a network system by which the generative cell becomes suspended and separated from the pollen grain wall. After the separation, the intine-3 layer is formed inside the intine 2. The generative cell wall and the intine-3 layer are formed by coated vesicles, polysaccharide particles and rough ER.     

A Comparative Study of Anther and Pollen Development in Male Fertile and Male. Sterile Green Onion (Allium fistulosum L.)

Anther and pollen development in male-fertile and male-sterile green onions was studied. In the male-fertile line, both meiotic microspore mother ceils and tetrads have a callose wall. Mature pollen grains are 2-celled. The elongated generative cell with two bended ends displays a PAS positive cell wall. The tapetum has the character of both secretory and invasive types. From microspore stage onwards, many oil bodies or masses accumulate in the cytoplasm of the tapetal cells. The tapetum degenerates at middle 2-celled pollen stage. In male-sterile line, meiosis in microspore mother cells proceeds normally to form the tetrads. Pollen abortion occurs at microspore with vacuole stage. Two types of pollen abortion were observed. In type I, the protoplasts of the microspores contract and gradually disintegrate. At the same time the cytoplasm of microspores accumulates oil bodies which remain in the empty pollen. The tapetal cells behave normally up to the microspore stage and early stage of microspore abortion, but contain fewer oil bodies or masses than those in the male-fertilt line. At late stage of microspore abortion, three forms of the tapetal ceils can be observed: (1) the tapetal cells with degenerating protoplasts become flattened, (2) the tapetal cells enlarge but protoplasts retractor, (3) the cells break down and tile middle layer enlarges. In type Ⅱ, the cytoplasm degenerates earlier than the nucleus of the microspores and no protoplast is found in the anther locule. There are fibrous thickenings iii the endothecium of both types. It is difficult to verify whether the tapetum behavior and pollen abortion is the cause or the effect.     

栽培甜菜花粉发育过程的超微结构

利用透射电镜技术对栽培甜菜(Beta vulgaris)花粉发育过程进行了超微结构观察。结果表明, 在小孢子母细胞减数分裂期间, 细胞内发生了“细胞质改组”, 主要表现在核糖体减少, 质体和线粒体结构发生了规律性变化。末期I 不形成细胞板,而是在2个子核间形成“细胞器带”。“细胞器带”的存在起到类似细胞板的作用, 暂时将细胞质分隔成两部分。四分体呈四面体型, 被胼胝质壁包围。小孢子外壁的沉积始于四分体晚期, 至小孢子晚期外壁已基本发育完全。单核小孢子时期, 细胞核大, 细胞器丰富。二细胞花粉发育主要表现在生殖细胞壁的变化上, 生殖细胞壁上不具有胞间连丝。成熟花粉为三细胞型, 含有1个营养细胞和2个精细胞。精细胞具有短尾突, 无壁, 为裸细胞, 每个精细胞通过2层质膜与营养细胞的细胞质分开。生殖细胞与精细胞里缺乏质体。     

栽培甜菜花粉发育过程的超微结构

利用透射电镜技术对栽培甜菜（Beta vuigaris）花粉发育过程进行了超微结构观察。结果表明,在小孢子母细胞减数分裂期间,细胞内发生了“细胞质改组”,主要表现在核糖体减少,质体和线粒体结构发生了规律性变化。末期1不形成细胞板,而是在2个子核间形成“细胞器带”。“细胞器带”的存在起到类似细胞板的作用,暂时将细胞质分隔成两部分。四分体呈四面体型,被胼胝质壁包围。小孢子外壁的沉积始于四分体晚期,至小孢子晚期外壁已基本发育完全。单核小孢子时期,细胞核大,细胞器丰富。二细胞花粉发育主要表现在生殖细胞壁的变化上,生殖细胞壁上不具有胞间连丝。成熟花粉为三细胞型,含有1个营养细胞和2个精细胞。精细胞具有短尾突,无壁,为裸细胞,每个精细胞通过2层质膜与营养细胞的细胞质分开。生殖细胞与精细胞里缺乏质体。     

Microspore development inBrassica napus and the effect of high temperature on division in vivo and in vitro

Summary Brassica napus cv. Topas microspores isolated and cultured near the first pollen mitosis and subjected to a heat treatment develop into haploid embryos at a frequency of about 20%. In order to obtain a greater understanding of the induction process and embryogenesis, transmission electron microscopy was used to study the development of pollen from the mid-uninucleate to the bicellular microspore stage. The effect of 24 h of high temperature (32.5 °C) on microspore development was examined by heat treating microspore cultures or entire plants. Mid-uninucleate microspores contained small vacuoles. Late-uninucleate vacuolate microspores contained a large vacuole. The large vacuole of the vacuolate stage was fragmented into numerous small vacuoles in the late-uninucleate stage. The late-uninucleate stage contained an increased number of ribosomes, a pollen coat covering the exine and a laterally positioned nucleus. Prior to the first pollen mitosis the nucleus of the lateuninucleate microspore appeared to be appressed to the plasma membrane; numerous perinuclear microtubules were observed. Microspores developing into pollen divided asymmetrically to form a large vegetative cell with amyloplasts and a small generative cell without plastids. The cells were separated by a lens-shaped cell wall which later diminished. At the late-bicellular stage the generative cell was observed within the vegetative cell. Starch and lipid reserves were present in the vegetative cell and the rough endoplasmic reticulum and Golgi were abundant. The microspore isolation procedure removed the pollen coat, but did not redistribute or alter the morphology of the organelles. Microspores cultured at 25 °C for 24 h resembled late-bicellular microspores except more starch and a thicker intine were present. A more equal division of microspores occurred during the 24 h heat treatment (32.5 °C) of the entire plant or of cultures. A planar wall separated the cells of the bicellular microspores. Both daughter cells contained plastids and the nuclei were of similar size. Cultured embryogenie microspores contained electron-dense deposits at the plasma membrane/cell wall interface, vesicle-like structures in the cell walls and organelle-free regions in the cytoplasm. The results are related to embryogenesis and a possible mechanism of induction is discussed.Abbreviations B binucleate - LU late uninucleate - LUV late uninucleate vacuolate - M mitotic - MU mid-uninucleate - RER rough endoplasmic reticulum - TEM transmission electron micrograph     

Ultrastructure of Male Gametophyte in wheat I. The Formation of Generative and Vegetative Cells

The present study of the formation of the generative and vegetative cells in wheat has demonstrated some cytological details at the ultrastructural level. The phragmoplast formed in telophase of the first microsporic mitosis extended centrifugally until it connected with the intine of the pollen grain. A new cell wall was then formed to separate the generative and the vegetative cells. By unequal cytokinesis the former is small and the latter large. In early developmental stage of male gametophyte, the organelles in the cytoplasm of the generaVive cell and the vegetative cells are similar, including mitochondria, dictyosomes, rough endoplasmic retieulum, free and clustered ribosomes and plastids, but microtubules were observed only in the early cytokinesis stage. In the further developmental stage of the male gemetophyte, the generative cell gradually detached from the intine of pollen grain and grew inward to the cytoplasm of the vegetation cell. When the generative cell became round and free in the cytoplasm of the vegetative cell, the wall materials between plasma membranes of the cytoplasm of the generative and the vegetative cells disappeared completely, so that it was a naked cell with a double-layer membrane at this time. The heterogeneity between both cells was then very conspiceous. The organelles in the cytoplasm of the generative cell have hardly any changed besides the degeneration of plastids, but in vegetative cytoplasm the mitochondria and plastids increased dramatically both in number and size. The rapid deposition of starch in the plastids of the cytoplasm of the vegetative cell made the most conspicuous feature of the vegetative cell in mature pollen grain. The significance of the presence of a temporary cell wall in generative cell and heterogeneity between generative and vegetative cells are discussed.     

Detection and quantification of rRNA by high-resolutionin situ hybridization in pollen grains

We examined changes in the localization of cytoplasmic rRNA during pollen development inNicotiana tabacum SR-1. The rRNA was visualized byin situ hybridization, and the signal intensity of rRNA in microspore, vegetative and generative cell was quantified by microphotometry. The amount of rRNA per microspore or pollen section increased about 5 times from microspore to mature pollen grain and kept increasing even in the late stage of pollen development after PMI. The increase of rRNA occur in both vegetative and generative cells. The results suggest that synthesis of rRNA occur even after PM I in both vegetative and generative cells.     

青葙花药发育的结构和组织化学观察

对苋科植物青葙Celosia argentea花药发育的结构和组织化学（多糖和脂滴）特征进行观察。青葙小孢子发生为同时型,四分体为四面体型。药壁为典型四层,绒毡层属于同型绒毡层。成熟花粉为二胞型。早期花药中的淀粉粒和脂滴均较少,绒毡层细胞至小孢子晚期退化为体积较大的脂块。二胞花粉时期的中层细胞退化为脂滴。早期二胞花粉中先出现多糖颗粒,晚期的成熟花粉中积累大量淀粉粒和较少的脂滴为营养储存物。