鹅掌楸油细胞发育过程中超微结构的变化与挥发油产生的关系

鹅掌楸[Liriodendron chinense(Hemsl.)Sargent.]油细胞的发育过程可依据细胞壁的结构变化依次划分为3个阶段,即仅具初生纤维素壁层阶段、木栓质化壁层形成阶段和内纤维素壁层形成阶段。在发育早期,仅具初生纤维素壁层时,油细胞因其体积大,核仁显著,含极少淀粉粒和质体几乎无类囊体而与周围的组织细胞不同。对其3个发育阶段中内部结构变化分析表明,挥发油合成于细胞质和质体中。细胞质中,挥发油就以小滴形式产生,然后逐渐与油囊融合直接贮入油囊,与此同时,在各种细胞器中,质体的变化最为明显,质体中合成的锇物质,随质体解体进入细胞质中,再经转化通过杯形构造积累入油囊。油囊中积累的油经OsO4染色后呈灰色,且分为2层,外层较内层深,推测与油的2种来源有关。     

薄荷盾状腺毛分泌过程的超微结构研究

电镜观察表明,刚形成的薄荷盾状腺毛的头部细胞,细胞核较大,细胞质浓,其中具一些小液泡,质体和线粒体丰富。分泌前期,质体和线粒体数量增加,体积扩大,质体内出现黑色嗜锇物质。以后,嗜锇物质从质体转移到细胞质中,通过小兴泡加工形成的灰色小滴形式进入液泡内,并在液泡内积累直至充满整个液泡。     

油樟油细胞和粘液细胞的发育解剖学研究

利用薄切片法对油樟茎叶油细胞和粘液细胞发育的研究结果表明,油细胞最早发生于第二叶原基以及茎端皮层和髓的基本分生组织中。未出现油细胞以前,在上述器官的基本分生组织和原分生组织中,难以区分油细胞的原始细胞与周围细胞,当油细胞原始细胞呈现出体积较大,液泡化程度较低,细胞核大而明显的特征才明显可辨,以后经过液泡融合,油细胞成熟和油细胞的细胞质解体阶段而成为一贮油的囊,而且油囊连接在杯形构造上,粘液细胞的早期发育过程与油细胞的相同,而在细胞液泡化的后期,靠近大液泡的细胞质中产生粘液物质。并扩散到大液泡中,粘液物质不断产生,变浓,占据整个细胞腔,细胞质解体后而成为完全成熟的粘液细胞,因此可见,油细胞和粘液细胞是同源的,也可能粘液细胞是由油细胞转化而来的。     

木姜子油细胞的发育解剖学研究

利用薄切片法对木姜子茎叶油细胞的发育以及油细胞分布的研究结果表明：油细胞最早发生于第一叶原基以及茎端皮层和髓的基本分生组织中,在未出现油细胞以痛,上述器官的基本分生组织和原分生组织,难以区分油细胞的原始细胞与周围细胞。当油细胞原始细胞呈现出体积较大,液泡化程度较低,细胞核大而明显的特征才明显可辩,以后经过液泡融合,油细胞成熟和油细胞细胞质解体阶段而成为一贮油的囊,油细胞中未出现杯形构造。叶和茎中,     

绵马鳞毛蕨精母细胞和游动精子超微结构特征的研究

应用电镜技术对蕨类植物绵马鳞毛蕨(RYOPTERIS CRASSIRHIZOMA Nakai)精母细胞和游动精子的超微结构特征进行了研究。精母细胞为多边形,细胞质内含有丰富的线粒体、质体、内质网、高尔基体等常见的细胞器．在细胞质中还可见到一些同心圆膜状结构,位于质膜的附近或精母细胞的角偶。同心圆膜状结构由双层膜环绕构成,外被l层单位膜。精母细胞与精子器的璧细胞之间形成了分离腔。在精母细胞质膜外形成了嗜锇层,这些结构的形成说明精母细胞已经开始与雄配子体逐渐分离,进入独立发育的阶段。尽管精母细胞之间也有嗜锇层的形成,但嗜锇层是不连续的,其上有一些空隙,精母细胞之间可通过空隙进行物质和信息的交流。成熟的精子细胞外被l层透明的薄膜,里面为游动精子。螺旋状。由环状细胞器环绕3～4圈构成．这些环状细胞器包括多层结卡构、微管带、巨大线粒体、鞭毛带和1个长形浓缩的细胞核。游动精子的后端为一些泡囊化的细胞质．其中包括一些残存的线粒体、造粉质体及大的囊泡等。当成熟的精子细胞排出精子器后。其内的游动精子挣脱透明质膜的束缚,摆脱后端的囊泡,成为1条游动精子。本文还对绵马鳞毛蕨和其它蕨类植物精子的超微结构特征进行了比较。     

抗病品种中小麦条锈菌细胞的超微结构变化过程

本文就寄主抗病性表达过程中,小麦条锈菌细胞的超微结构变化进行了系统地观察研究。结果表明:胞间菌丝的细胞壁染色逐渐加深,厚度加宽,结构疏松,形成小空洞,并逐渐解体;细胞质逐渐凝聚、脂肪粒的数量增多、有黑色颗粒状沉积物积累;细胞质中小囊泡数目增多并逐渐融合成大液泡,线粒体数目增多,并逐渐肿胀和解体。次生吸器畸形,初生吸器体呈圆球形。吸器壁加厚,染色加深;在吸器的中央,细胞质逐渐分解而形成空泡;线粒体数目增多,并逐渐肿胀和解体;吸器外质膜呈皱褶状,吸器外间质加宽,其中有大量的丝状或颗粒状内含物形成;吸器形态结构的变化均早于其胞间菌丝。     

鹅掌楸油细胞的发育解剖学研究

鹅掌楸油细胞比相邻组织细胞分化,因而在叶肉细胞未完全分化的叶原基、幼叶以及未完全分化的幼茎中,都可看到已分化的油细胞。通常,在第二叶原基中可发现油细胞原始细胞,由于其染色深、细胞核大而易与周围组织的细胞相区别。以后,油细胞逐步液泡化,直至形成一个大的液泡,此时,细胞核呈扁平状,并与细胞质一起成为一薄层围绕着大液泡。当油细胞发育成熟后,细胞质及核开始解体,整个油细胞的腔由大液泡充满,成为油囊,在部分     

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。     

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。     

贯叶连翘的分泌结构及其与金丝桃素积累的关系

贯叶连翘（ＨｙｐｅｒｉｃｕｍｐｅｒｆｏｒａｔｕｍＬ．）地上器官分布着分泌细胞球（黑色腺点）、分泌囊（半透明腺点）和分泌道（半透明腺条）３类内部分泌结构。分泌细胞球在茎、叶和花器官中均有分布,由２层鞘细胞包围多个分泌细胞构成实心的分泌细胞团。分泌囊主要分布于叶片中,分泌道则分布于花器官中,它们都是由１～２层切向扁平细胞围绕圆形或长形腔道构成,腔道的贮存物为精油。利用组织化学方法,结合荧光显微镜观察,证实金丝桃素类物质是由分泌细胞球（黑色腺点）所合成和积累的。通过用戊二醛和锇酸固定样品的显微和超微结构观察,发现金丝桃素类物质积累在成熟腺体分泌细胞的中央大液泡中,细胞周围浓厚的细胞质中分布着大量小液泡和高尔基体、内质网等细胞器。在此基础上对金丝桃素类物质的积累过程进行了初步探讨     

Ultrastructural Studies on the Development of Oil Cells in Litsea pungens

The developmental process of oil cells in the shoot of Litsea pungens Hemsl. has been studied with transmission electron microscopy. According to the development of the three layers of cell wall, the developmental process could be divided into 4 stages. In stage 1, the cell wall consisted only of a primary (the outmost) cellulose layer, which might further be divided into two substages, the oil cell initial, and the vacuolizing oil cell. During this stage, there were some small electron translucent vesicles and dark osmiophilic droplets of variant sizes in the different-shaped plastids. It was observed that some dark and gray osmiophilic materials coalesced to vacuoles in the cytoplasm. In stage 2, a lamellated suberin layer accumulated inside the primary cellulose layer. In stage 3, a thicker and looser inner cellulose wall layer was formed gradually inside the suberin layer. Some dark osmiophilic droplets have been observed in this loose inner cellulose wall layer. The plasmodesmata were blocked up and became a special structure. Then, the big vacuole, which is the oil sac, was full of osmiophilic oil. In stage 4, the oil cell became matured and the cytoplasm disintegrated. The oil sac enveloped from plasmalemma was attached to the cupule, which was formed by the protuberance of the inner cellulose wall layer into the lumen. After the maturity of oil cell, the ground cytoplasm began to disintegrate and became electron opaque or exhibited in a disordered state, and the osmiophilic oil appeared light gray.     

Ultrastructure and development of oil cells in Laurus nobilis L. leaves

The oil cell development in Laurus nobilis leaves has been studied. At the early developmental stage, when the cell wall consists of the outer cellulose wall only, the oil cells differ from the neighbouring mesophyll cells in their larger size, lower starch content and in their plastid organization. After the deposition of the lamellated suberin layer and the inner cellulose layer, a wall protuberance (cupule) is formed on the periclinal wall facing the epidermis. From its reaction with periodic acid-hexamine-silver nitrate, it is suggested that the cupule is cellulosic. The portion of the inner cellulose wall layer bearing the cupule seems to contain patches of suberin. Plasmodesmata occur in special wall protuberances and appear to become occluded with age. The oil produced inside the protoplast is secreted to the outside of the plasmalemma, and accumulates as a drop at the place predetermined by the cupule. Except at the cupule, the oil drop is surrounded by the plasmalemma.     

Ultrastructure and Development of Oil Idioblasts in Annona muricata L.

The ultrastructure and development of oil idioblasts in theshoot apex and leaves in Annona muricata L. are described, andthree arbitrary developmental stages are distinguished: cellsin which no additional cell wall layers have been depositedagainst the initial primary cell wall, possessing an electron-translucentcytoplasm and distinct plastids which lack thylakoids (stage1); cells in which a suberized layer has been deposited againstthe primary wall (stage 2, the cytoplasm resembles that of thepreceding stage), and cells in which an additional inner walllayer has been deposited against the suberized layer, whichincreases in thickness with development (stage 3). In this stagean oil cavity is formed, surrounded by the plasmalemma, andattached to a bell-like protrusion of the inner wall layer,the cupule. A complex membranous structure occurs next to thecupule. Smooth tubular endoplasmic reticulum (ER), appearingas linearly arranged tubules, and groups of crystalline bodieswith an almost hexagonal outline are present. The final stagewas further subdivided into three subgroups (a, b, c) basedon the extent of the oil cavity, its contents, and the compositionof the cytoplasm, and increasing thickness of the inner walllayer. The oil is probably synthesized in the plastids, releasedinto the cytoplasm, and then passed through the plasmalemmasurrounding the oil cavity. Oil idioblasts, Annona muricata L., suberized layer, inner wall layer, oil cavity, cupule, smooth tubular ER, crystalline bodies     

The development of the endoder mis andPhi layer of apple roots

Summary Suberin lamellae and a tertiary cellulose wall in endodermal cells are deposited much closer to the tip of apple roots than of annual roots. Casparian strips and lignified thickenings differentiate in the anticlinal walls of all endodermal andphi layer cells respectively, 4–5 mm from the root tip. 16 mm from the root tip and only in the endodermis opposite the phloem poles, suberin lamellae are laid down on the inner surface of the cell walls, followed 35 mm from the root tip by an additional cellulosic layer. Coincidentally with this last development, the suberin and cellulose layers detach from the outer tangential walls and the cytoplasm fragments. 85 mm from the root tip the xylem pole endodermis (50% of the endodermis) develops similarly, but does not collapse. 100–150 mm from the root tip, the surface colour of the root changes from white to brown, a phellogen develops from the pericycle and sloughing of the cortex begins. A few secondary xylem elements are visible at this stage.Plasmodesmata traverse the suberin and cellulose layers of the endodermis, but their greater frequency in the outer tangential and radial walls of thephi layer when compared with the endodermis suggests that this layer may regulate the inflow of water and nutrients to the stele.     

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.     

蕨类植物紫萁绒毡层细胞凋亡的细胞学特征

绒毡层凋亡过程是小孢子发生中的重要事件,以往的研究主要集中在被子植物,蕨类植物尚未见此方面的报道。该研究首次采用透射电镜和免疫荧光技术对蕨类植物紫萁(Osmunda japonica Thunb.)绒毡层细胞凋亡的细胞学过程进行了观察,以明确紫萁绒毡层细胞的发育类型和凋亡特征,为蕨类植物绒毡层细胞凋亡的深入研究以及孢子发育研究提供依据。结果显示：(1)紫萁的绒毡层属于复合型,即外层绒毡层为分泌型,该层细胞发育过程中液泡化,营养物质被吸收;内层绒毡层为原生质团型,经历了细胞凋亡的过程。(2)绒毡层内层细胞在凋亡过程中细胞壁和细胞膜降解,细胞质浓缩且空泡化;细胞核内陷、变形,染色质浓缩凝聚,形成多数小核仁,DAPI荧光由强变弱;线粒体、质体、内质网、高尔基体等细胞器逐渐退化,液泡中多包含纤维状物、絮状物、黑色嗜锇颗粒和小囊泡等;出现多泡体、多膜体和细胞质凋亡小体,上述特征与种子植物绒毡层凋亡特征基本一致。(3)与种子植物相比,紫萁绒毡层的细胞凋亡开始得早,在整个凋亡过程中没有核凋亡小体的产生;除了产生孢粉素外,绒毡层细胞内产生了大量的丝状物质、絮状物质和电子染色暗的颗粒物,这些物质可能用于...     

Studies of Ultrastructure and ATPase Localization of Mature Embryo Sac in Vicia faba L.

Studies of ultrastructure and ATPase localization of the mature embryo sac in Vicia faba L. show that the egg cell has no cell wall at thechalazal end, it has a chalazally located nucleus and a large micropylar vacuole. There are many nuclear pores in the nuclear membrane. The cytoplasm is restricted around the nucleus. Dictyosome and mitochondria are few. There are some starch grains and lipid grains in the egg cytoplasm. There are no obvious differences between two synergids. No cell wall is seen at the chalazal end either, but there are some vesicles which project to vacuole of the central cell and fuse with its vacuolar membrane. Plasmodesmata connections occur within the synergid wall where it is adjacent to the central cell. The synergid has a micropylarly located nucleus and a chalazal vacuole, the nucleus is irregularly shaped. The synergid cytoplasm is rich in organelles. The filiform aparatus is of relatively heterogeneous structure. The central cell is occupied by a large vacuole and its cytoplasm is confined to a thin layer along the empryo sac wall, but is rich in various organelles, starch grains and lipid bodies. Nucleolar vacuoles are often present two polar nuclei. The nuclear membranes of two polar nuclei have partly fused. ATPase reactive product was located obviously at the endoplasmic reticulum in cytoplasm of the egg cell and central cell. The embryo sac wall consists of different density of osmiophilic layer. There are some wall ingrowths in chalazal region of the embryo sac. The long-shaped and cuneate cells of chalazal region are peculiar. Special tracks of ATPase reactive products are visible at their intercellular space which may be related to transportation of nutrients.     

An impregnated suberized wall layer in laticifers of theConvolvulaceae,and its resemblance to that in walls of oil cells

Summary The cell wall in laticifers of theConvolvulaceae, Calystegia silvatica, C. soldanella, C. tuguriorum, Convolvulus cneorum, C. verecundus, C. sabaticus subsp.mauritanicus, andIpomoea indica, contains an impregnated layer that surrounds the cells. The impregnated layer lies inside the primary wall of the laticifer, separated from the protoplast by a third (tertiary) layer of variable thickness. Histochemical and cytochemical staining give a positive reaction for suberin. The layer is often differentiated into dark and translucent regions, the latter frequently being composed of lamellae. The ultrastructure of this layer and its position within the cell wall of the laticifer is comparable to the condition found in oil cells where the walls contain a suberized layer. A suberized layer within the wall is unique for a laticifer system.     

Seed Epidermis Development and Histochemistry in Solanum melongena L. and S. violaceum Ort.

Structure, development and histochemistry of the seed epidermiswere studied inSolanum melongena L. andS. violaceum Ort. usinglight and scanning electron microscopy. The epidermal cellsat the endosperm mother cell stage of ovule development hadthickened outer periclinal walls, consisting of two layers,a thin inner layer, and a thick outer layer. The latter whichstained positively for pectic substances became further thickenedduring the course of seed development; more so inS. melongena.The inner layer of the outer periclinal wall also was thickenedby depositions of cellulose but remained comparatively thin.The development of the inner periclinal and anticlinal wallstook place by the uneven deposition of concentric layers. Thesesecondary wall thickenings which appeared as pyramids in transversesection stained for cellulose, lignin and pectin. Further unevensecondary thickenings near the outer part of the anticlinalwalls resulted in the formation of projections which were hair-or ribbon-like in appearance. InS. melongena, these projectionsprogressed only a short distance from the anticlinal wall. InS.violaceum, on the other hand, they grew much longer formingstriations on the inside of the outer periclinal wall. InS.melongena, partial removal of the outer periclinal wall by enzymeetching exposed to surface view a beaded appearance of the cellboundaries. Complete erosion of the outer periclinal wall revealedthe hair-like projections of the underlying anticlinal walls.InS. violaceum, enzyme treatment exposed the striations whichformed bridge-like structures over the curves in the anticlinalwalls. Solanum melongena ; Solanum violaceum; seed epidermis; seed structure; seed development; cell wall histochemistry; cell wall projections; cell wall striations