洋葱花药发育中钙离子分布特征

采用焦锑酸钾沉淀钙离子技术,对洋葱（Alliumcepa）花药发育中Ca^2＋分布进行了研究。在小孢子母细胞时期,小孢子母细胞中的钙沉淀颗粒很少,但绒毡层细胞的内切向壁已出现明显的钙沉淀颗粒。在四分体时期,四分体小孢子的胼胝质壁中出现较多的钙沉淀颗粒;绒毡层细胞内切向壁的钙沉淀颗粒消失,而在外切向壁和径向壁部位的钙沉淀颗粒增加。在小孢子早期,小孢子中也出现了钙沉淀颗粒,而绒毡层细胞内切向壁表面出现了很多絮状物,其上附有细小钙沉淀颗粒。到小孢子晚期,小孢子中出现一些小液泡,细胞质中的钙沉淀颗粒有所下降。此时绒毡层细胞已明显退化,但在绒毡层膜上仍有一些乌氏体和钙沉淀颗粒。在二胞花粉早期,营养细胞中的液泡收缩、消失,细胞质中又出现了较多的钙沉淀颗粒,在质体和其内部的淀粉粒表面上附有较多的钙沉淀颗粒。到二胞花粉晚期,花粉中的钙沉淀颗粒已明显下降,仅在花粉外壁中还有一地钙沉淀颗粒．     

杉木小孢子叶球发育过程中形态结构变化

以扬州地区生长的成年杉木为实验材料,通过采用数码相机拍摄、体视镜、扫描电镜以及半薄切片等方法,对杉木小孢子叶球发育、小孢子囊发育及其散粉规律进行详细观察。结果发现,10月中旬,杉木小孢子叶球形成并着生于新枝顶端。翌年3月中下旬,小孢子叶球成熟,进入散粉期,散粉首先从小孢子叶球基部开始依次向上部扩散。小孢子叶在孢子叶球主轴上螺旋排列,单个小孢子叶通常由3个小孢子囊组成,构成三角形。小孢子囊壁由1层表皮细胞、1~2层中间层细胞和1层绒毡层细胞组成,表皮细胞首先形成,并向内分化出2~3层细胞,分别分化形成中层和绒毡层,最后中层和绒毡层消失。杉木的小孢子囊通过开裂口控制其开裂,20℃室温下整个小孢子叶球散粉时间持续约18 h,单个小孢子叶的散粉时间为8~10 h。以上结果显示,杉木小孢子叶球的发育过程经历了体积增大、鳞片开张及散粉等阶段,这些形态和结构上的变化利于提高散粉效率,这说明杉木在长期的演化过程中,形成了许多有利于风媒传粉的结构特征。     

阳春砂花药发育过程的组织化学研究

用环氧树脂包埋的半薄切片经PAS反应和苏丹黑染色,研究阳春砂花药发育中的多糖和脂类物质分布特征。结果发现小孢子母细胞和四分体小孢子中积累了一些脂滴,但没有淀粉。阳春砂小孢子母细胞和四分体没有胼胝质壁。晚期小孢子中除了仍有很多脂滴外,细胞核周围开始出现淀粉粒;成熟花粉粒贮存丰富的淀粉粒和脂滴,且花粉壁由多糖物质构成。阳春砂花药壁结构比较特殊:花药壁由10余层细胞组成;最内层的绒毡层细胞在小孢子时期开始解体,细胞质转变为脂滴,供花粉吸收。开花时,花药壁由表皮和几层薄壁细胞以及径向壁纤维加厚的变形细胞组成。     

利用洋葱鳞叶表皮细胞观察植物细胞结构实验的改进

以洋葱表皮细胞为研究材料,通过中性红液泡染色和质壁分离实验相结合,将能更清晰地观察到细胞壁,细胞质膜,细胞质,液泡膜,液泡,细胞核,核仁等结构,达到光学显微镜下观察植物细胞基本结构的教学目的。改进后的实验大大提高了利用洋葱表皮细胞观察植物细胞结构实验的教学效果,同时可以通过观察不同部位液泡体积变化,了解植物细胞的动态发育,使学生掌握了更多的知识点。     

侧柏小孢子囊壁绒毡层和中层细胞的发育

侧柏[Platycladus orientalis (L.)Franco]小孢子囊壁包括3层细胞：表皮、中层和绒毡层。中层细胞为1层扁平的细胞。绒毡尾细胞属于分泌型。成熟的绒毡层细胞除了有单核和双核细胞外,还有三核和四核等多核细胞,细胞核有圆形和长椭圆形2种形态。绒毡层细胞的洒色质伴随着小孢子母细胞减数分裂有一个浓缩和伸展的时期,这个时期影响营养物质向小孢子囊内部转运,绒毡层细胞发育的初期就为造孢细胞提供营养,后期解体时,分泌的乌氏体不是散乱地而是有组织地向花粉粒的表面转移。中层和绒毡层细胞最终作为营养被全部吸收利用。     

中国蜘蛛抱蛋属植物营养器官的解剖学研究

首次对中国蜘蛛抱蛋属 9种植物的营养器官进行了解剖学研究。结果表明 :该属 9种植物的解剖结构基本相同。根和根状茎都由表皮、皮层和维管柱组成。根表皮下有单层薄壁细胞 ;内、外皮层均为一层五面加厚的厚壁细胞 ,内皮层外切向壁薄 ,呈马蹄形 ,外皮层内切向壁薄而外切向壁特别加厚 ,并栓质化 ,在横切面上形成一明显的厚壁组织环带 ;根为多原形。根状茎有明显的内皮层 ,周木维管束散生于维管柱的基本组织中 ;具有次生结构 ,次生保护组织为周皮。叶为等面叶 ,具有C4植物结构特征 ;气孔在上、下表皮均有分布 ,保卫细胞肾形 ,属四轮列型。该属植物的解剖结构与其生态环境相适应 ,体现了结构与功能的统一。     

莴苣花药发育过程中钙的分布特征

减数分裂前,莴苣花药中的钙颗粒很少。减数分裂后,花药绒毡层细胞中的钙颗粒明显增加。同时在花药药室基质中也出现许多细小的钙颗粒。刚从四分体中释放出的小孢子内钙颗粒很少。伴随着花粉外壁物质在小孢子表面的沉积,钙颗粒开始积累在花粉壁部位。随后。小孢子中开始出现钙颗粒。当小孢子开始形成液泡后,钙颗粒向其中聚集,伴随着小液泡融合成大液泡。体积较大的钙颗粒主要集中在液泡中,而细胞质基质中的钙颗粒很少。随着二胞花粉中的大液泡消失,花粉细胞质中的钙颗粒变得很少。在以后的发育中,只有花粉壁中积累较多的钙颗粒。在莴苣花药发育过程中,钙与绒毡层细胞的退化和小孢子液泡形成以及二胞花粉中大液泡的消失有关。而花粉外壁表面积累丰富的钙与以后花粉的萌发有关。     

莴苣花药发育过程中钙的分布特征

减数分裂前,莴苣花药中的钙颗粒很少。减数分裂后,花药绒毡层细胞中的钙颗粒明显增加, 同时在花药药室基质中也出现许多细小的钙颗粒。刚从四分体中释放出的小孢子内钙颗粒很少,伴随着花粉外壁物质在小孢子表面的沉积,钙颗粒开始积累在花粉壁部位。随后,小孢子中开始出现钙颗粒。当小孢子开始形成液泡后,钙颗粒向其中聚集,伴随着小液泡融合成大液泡,体积较大的钙颗粒主要集中在液泡中,而细胞质基质中的钙颗粒很少。随着二胞花粉中的大液泡消失,花粉细胞质中的钙颗粒变得很少。在以后的发育中,只有花粉壁中积累较多的钙颗粒。在莴苣花药发育过程中,钙与绒毡层细胞的退化和小孢子液泡形成以及二胞花粉中大波泡的消失有关。而花粉外壁表面积累丰富的钙与以后花粉的萌发有关。     

杜仲胚胎学的研究——Ⅱ.雄配子体的发育

杜仲(Eucommia ulmoides Oliv)小孢子母细胞减数分裂属同时型。小孢子阶段短暂,当细胞体积略增大,未形成液泡时,细胞核由中部移向边缘即进行第一次分裂。在分裂中期,多数纺锤体轴垂直于花粉壁,呈不对称形;少数平行于壁,其两极相似。分裂过程中细胞质内逐渐形成几个大液泡,并消耗贮藏淀粉。生殖细胞位于边缘时,与营养细胞间的拱形壁呈PAS正反应。随后当生殖细胞内移到营养细胞质内的过程中,液泡逐渐解体,贮藏物质重新累积,花粉体积增大。成熟花粉具三沟孔,二细胞型。花粉管单一无分枝,当生殖细胞在花粉管中分裂时,营养核由椭圆形变长,结构松散,并处于其近侧。二个精子一前一后相接近,营养核紧邻其前端,未见有在其后面的现象。     

热胁迫对辣椒花药发育过程中Ca2+分布的影响

运用焦锑酸钾沉淀法,研究了不同热胁迫时间对辣椒（Capsicum annuum L.)小孢子发生和花粉发育过程中Ca^2 分布的影响。在小孢子母细胞中,细胞表面有少量Ca^2 分布,细胞核中基本上观察不到Ca^2 ,热胁迫12h后,细胞质和细胞核中Ca^2 明显增多,液泡膜内侧也有许多Ca^2 分布,热胁迫24h后,大量的Ca^2 分布在细胞质中,液泡膜上和液泡内;在四分体时期,与小孢子母细胞相比,四分小孢子表面和细胞质中Ca^2 数量明显增加,热胁迫24h后,细胞质和细胞核中Ca^2 更多;在小孢子中,大量Ca^2 分布在壁上,质膜内侧,液泡膜上,少量分布在细胞质和细胞核中,热胁迫12h后,质膜上Ca^2 增多,24h后,细胞质,细胞核中,质膜内侧的Ca^2 继续增多,热胁迫对成熟花粉中Ca^2 的分布无明显影响。     

ELECTRON MICROSCOPE STUDY OF MYCOBACTERIUM LEPRAE AND ITS ENVIRONMENT IN A VESICULAR LEPROUS LESION.

Imaeda, Tamotsu (Instituto Venezolano de Investigaciones Cientificas, Caracas, Venezuela) and Jacinto Convit. Electron microscope study of Mycobacterium leprae and its environment in a vesicular leprous lesion. J. Bacteriol. 83:43-52. 1962.-Biopsied specimens of a borderline leprosy lesion were observed with the electron microscope. In this lesion, the majority of Mycobacterium leprae were laden with cytoplasmic components. The bacilli were separated from the cytoplasm of host cells by an enclosing membrane, thus differing from the environment of well-developed lepra cells in lepromatous lesions.The cell wall is composed of a moderately dense layer. A diffuse layer is discernible outside the cell wall, separated from it by a low density space. It is suggested that the cell wall is further coated by a low density layer, although the nature of the outermost diffuse layer has not yet been determined.The plasma membrane consists of a double layer, i.e., dense inner and outer layers separated by a low density space. The outer layer is closely adjacent to the cell wall. In the region where the outer layer of the plasma membrane enters the cytoplasm and is transformed into a complex membranous structure, the inner layer encloses this membranous configuration. Together they form the intracytoplasmic membrane system.In the bacterial cytoplasm, moderately dense, presumably polyphosphate bodies are apparent. As neither these bodies nor the intracytoplasmic membrane system are visible in the degenerating bacilli, it seems probable that these two components represent indicators of the state of bacillary activity.     

Electron microscopy of germinating ascospores ofSaccharomyces cerevisiae

The wall of mature ascospores ofSaccharomyces cerevisiae showed in sections under the electron microscope a dark outer layer and a lighter inner layer. The latter was composed of a greyish inner part and a light outer part. During germination, the spore grew out at one side and the dark outer layer was broken. Of the light inner layer, the inner greyish part became the wall of the vegetative cell, but the extented part of the cell had a new wall.     

Structure of the endosperm in the mature seed of Melilotus alba]

The results of the exam at the light, the fluorescence and the scanning electron microscope of the endosperm of Melilotus alba mature impermeable seeds are reported. Cryostat sections, semithin sections and squashes are observed. Melilotus alba endosperm is variable in thickness and envelopes cotyledons and radicle. Its "aleurone" layer is one-cell thick, while the number of layers of its internal cells varies in relation to the location in the seed. In the aleurone cells, the cytoplasm and the outer portion of the wall are autofluorescent; tannic acid-ferric chloride stains the outer portion of the wall and allows to see clearly the inner thickenings, DAPI and haematoxylin demonstrate the presence of the nucleus. The cytoplasm of these cells is coloured by Sudan black b, and its fluorescence is enhanced by auramine and calcofluor white. Calcofluor white enhances the fluorescence of the outer portion of these walls, too, but is without effect on the non-autofluorescent thickening, indicating presence of cellulose only in the first case. Callose is absent. Also the thin autofluorescent walls of the endosperm inner cells react positively to calcofluor. These cells are very large, almost completely filled with "gelatinous" substances--the galactomannans--and very rarely contain a nucleus.     

Organization of mature external glands on the trap and other organs of the bladderwortUtricularia monanthos

Summary The mature dome-shaped glands which cover the outer surfaces of the trap, leaves, anchor and runner stolons inU. monanthos are described using conventional and some high voltage transmission electron microscopy. The glands occur as scattered ordinary external glands and as a compact clump of vestibule glands at the entrance to the doorway. Each gland rests on a basal epidermal cell and consists of a single pedestal and terminal cell. Vestibule and leaf glands differ slightly from the other glands mainly in the structure of the outer wall of the terminal cell. Nuclear crystals are prominent and the cytoplasm of the pedestal and terminal cells contains tubular structures usually aggregated near the nucleus. The pedestal cell is a transfer cell with short wall protuberances on the outer wall, conspicuous mitochondria and a heavily impregnated lateral wall.The terminal cell often has an outer wall that is greatly thickened and a protoplast that may degenerate early. In the most developed cells the protoplast remains active for a long period and the outer wall is differentiated into several layers. The outermost layer is cuticularized consisting of an open meshwork of deposits. In leaf glands a local polysaccharide mass is usually developed within the cuticularized region. The inner non-impregnated region of the outer wall may show four layers. In vestibule glands fewer layers are present and the wall shows prominent lamellations. Some ordinary external glands differentiate a sponge-like substructure within the inner wall.The ultrastructure and function of the glands are discussed. We support the concept that mature external glands are responsible for secreting water, with those on traps being particularly active during the resetting of the organ. Our work provides a structural basis for recent suggestions by other workers that the mechanism of secretion probably involves establishing a standing osmotic gradient within the gland.     

The Fine Structure of Haemoproteus columbae Sporozoites*

SYNOPSIS. The fine structure of Haemoproteus columbae sporozoites has been studied and compared to sporozoite structure as revealed by the light microscope. The sporozoites are ultrastructurally similar to those of other Haemosporidia in that they possess a 3-layered pellicle, subpellicular microtubules, polar ring, micropore, free ribosome-like particles, micronemes, a structure resembling a Golgi complex, an irregular mitochondrion, and a large nucleus. In the anterior region of the sporozoite there are 21–22 regularly arranged longitudinal subpellicular microtubules located peripherally around the cell. In the apical region the microtubules appear thickened on 1 side. The sporozoite of H. columbae has a microneme system in which 1–3 micronemes are associated with the outer pellicular membrane at the anterior end. Micronemes are found throughout the cytoplasm, but occur in greater concentration in the anterior region of the sporozoite. A clear pellicular cavity, located between the polar ring and the termination of the inner pellicular layer, is present at the anterior end of the sporozoite. Vesicular invaginations of the inner pellicular layer have been observed in the anterior region; their function is unknown. Spherical osmophilic bodies are found throughout the cytoplasm.     

ULTRASTRUCTURAL STUDY ON SPORE WALL MORPHOGENESIS IN LYCOPODIUM CLAVATUM (LYCOPODIACEAE)

Spore wall morphogenesis of Lycopodium clavatum was observed by transmission electron microscopy. The spore plasma membrane indicates the reticulate spore sculpture shortly after meiosis. The mature spore wall of this species consists of two layers, inner endospore and outer exospore. There is no perispore in the sporoderm of this species. The exospore formation begins during the tetrad stage; and this layer is divided into two distinct sublayers, an outer lamellar layer and an inner granular layer. The lamellar layer is formed on the sculptured spore plasma membrane. Additional lamellae attach to this layer in a centripetal direction. For that reason, this layer may be derived from spore cytoplasm. The granular layer is formed only in the proximal region following lamellar layer formation, and it also may be derived from spore cytoplasm. The endospore is formed lastly and seems to be derived from spore cytoplasm as well. Accordingly, the spore sculpture of this species may be under the genetic control of the spore nucleus.     

白刺胚乳早期发育的超微结构研究

白刺(Nitraria sibirica)胚乳发育经历游离核阶段、细胞化阶段和被吸收解体阶段。游离核胚乳沿胚囊壁均匀排列为一层,胞质浓厚,其中有丰富的质体、线粒体、高尔基体、内质网和各种小泡等细胞器。珠孔区域的胚囊壁具发达的分枝状壁内突,而周缘区域的胚囊壁具间隔的钉状内突,内突周围的细胞质中具多数线粒体和小泡。胚乳细胞化时,初始垂周壁源于核有丝分裂产生的细胞板。在细胞板两端开始壁的游离生长,一端与胚囊壁相连接,另一端向心自由延伸。壁的游离生长依赖于小泡的融合。早期胚乳细胞具大液泡,具核或无核,细胞质中有大量的线粒体,质体缺乏,其壁仍由多层膜结构组成。     

舞花姜种子的解剖学和组织化学研究

舞花姜种子表面只许多表皮毛,基部具黄白色的种阜状结构。假种皮着生于种阜结构内缘,基部筒状,中上部指状分裂;假种皮细胞长条形．内含许多细小淀粉粒。种皮由外珠被发育而来．可划分为外种皮、中种皮与内种皮。外种皮由具３—５（６）层表皮细胞的复表在构成,最外层的一些表皮细胞向强突起形成表皮毛。中种皮由下皮层、半透明细胞层、中种皮薄壁细胞层与色素层构成。下皮层由一层下皮细胞构成,细胞内充满结合有单字的红褐色色素;半透明细胞含有与脂类结合的淡黄褐色无定形块状物,中种皮薄壁细胞内无色素或任何颗粒状物;色素层为中种皮最内方的一层,细胞体积大、充满与单宁结合的红褐色色素。内种在由一层体积小、壁局部增厚的砖形薄壁细胞构成,其机械保护作用小。种子在珠孔区分化出珠孔领、孔盖及种阜状结构。珠孔领为异形型,孔盖不具石细胞硬层。种阜状结构以其细胞层数增多、壁增厚并本质化的复表皮加强了珠孔区的机械保护作用。合点区内种皮出现缺口．缺口间充满通常呈多角形的合点区色素细胞,其整体轮廓为长条形。外胚乳细胞壁平直,细胞内充满淀粉粒,部分细胞还含有少量的蛋白质与脂类：近合点外胚乳形成一薄区。内胚乳细胞含有蛋白质、脂类与淀粉．其细胞轮廓清楚,椭圆形或不规?     

ULTRASTRUCTURE OF THE DEVELOPING MEGASPORE MOTHER CELL OF GINKGO BILOBA

The immature megaspore mother cell of Ginkgo biloba is essentially spherical and is surrounded by a thick, complex wall. A large nucleus occupies the central region of the cell, and the organelles appear to be randomly arranged in the cytoplasm. With approaching maturity and the onset of meiosis, the cell elongates in the direction of the ovular axis. An extensive system of ER develops at the micropylar pole of the cell during elongation, and the plastids and mitochondria migrate to the opposite or chalazal pole. The micropylar end of the mature megaspore mother cell is usually devoid of plastids and mitochondria, but these organelles are densely packed in the chalazal end of the cell below the nucleus. The dictyosomes and dense spherosome-like bodies do not show such polarity in their distribution. At meiosis I plastids and mitochondria are, as a rule, restricted to the chalazal dyad cell that is destined to produce the functional megaspore. The wall of the megaspore mother cell consists of a middle lamella which is irregularly thickened, an outer wall layer resembling the walls of the surrounding nutritive cells, and an inner layer resembling the middle lamella in appearance.