几种高山植物叶绿体淀粉粒的变化特征

利用透射电镜对生长于青藏高原东北部达坂山（海拔3900m）的5种高山植物叶绿体超微结构进行了观察。结果发现,在所研究的5种高山植物叶绿体中,淀粉粒数量均较多,淀粉粒呈长椭圆形或圆形,沿叶绿体长轴分布。在珠芽蓼的叶绿体中,淀粉粒的电子密度内外不均匀,外周电子密度低,中央电子密度高。在其余4种高山植物中,淀粉粒的电子密度均较低。另外,在这5种高山植物叶绿体中还出现了脂质小球。其类囊体均出现了不同程度的膨大现象。研究表明,高山植物叶绿体中淀粉粒的这种变化是对逆境的一种适应,是青藏高原特殊生态条件长期胁迫的结果。     

冬季沙冬青细胞质中一种高电子密度结构的电镜观察

用透射电子显微镜观察了冬季沙冬青的叶肉细胞。观察表明,其细胞质中有一种电子密度很高的结构,分布广,主要位于有一定解体现象并含有较多嗜锇小球叶绿体附近,有的甚至与叶绿体被膜贴在一起,很少存在于发育良好的叶绿体附近和液泡中。其大小不同,通常为椭圆形,有时也近似圆形。表面没有包围膜,泡状结构少,常有突起。这种结构的电子密度很高,染色较均匀,冬季大量出现可能与提高植物的抗寒性有关.     

CO2浓度倍增对谷子和紫花苜蓿叶绿体超微结构的效应

电镜观察结果表明,不同种类植物生长在相同倍增的高ＣＯ２ 浓度条件下,其叶绿体超微结构彼此呈现出明显的差异． 最醒目的特征是淀粉粒的积累比对照的增加很多;类囊体膜系发生异变． 总体上,（１）淀粉粒,Ｃ４ 植物谷子（Ｓｅｔａｒｉａ ｉｔａｌｉｃａ）叶绿体比Ｃ３ 植物紫花苜蓿（Ｍｅｄｉｃａｇｏ ｓａｔｉｖａ）积累的更多． （２）淀粉粒较小且较少时,紫花苜蓿叶绿体基粒类囊体膜增多,与基质类囊体膜相间排列有序;谷子叶绿体的基粒垛及基粒类囊体膜数均增多,但基粒变小,基质类囊体膜变长,且有些膜出现膨胀甚至破损． （３）淀粉粒较大且积累过多时,紫花苜蓿叶绿体中尚可隐约见到由４～８ 个类囊体膜组成的短小基粒零星分布于淀粉粒间;谷子叶绿体中几乎找不到可辨认的基粒和基质类囊体膜     

盐胁迫下芦苇叶肉细胞超微结构的研究

对青藏高原柴达木盆地柯柯盐湖边盐碱地上生长的芦苇叶肉细胞的超微结构进行了研究,并以西宁地区非盐碱地上生长的芦苇作对照。结果表明：西宁地区的芦苇叶肉细胞的叶绿体呈椭圆形,其膜系统完整,基粒片层和基质片层发育良好。在盐碱地上生长的芦苇叶肉细胞的叶绿体呈圆形,叶绿体内出现较大的淀粉粒,并发现有线粒体嵌入叶绿体的现象。叶绿体的类囊体膨大,线粒体的嵴也有膨大的现象。在盐湖水中生长的芦苇叶肉细胞,叶绿体的类囊体排列紊乱、扭曲、松散。类囊体膜局部被破坏,部分类囊体膜解体,空泡化,甚至消失,一些溶解了的类囊体流进细胞质中。综上所述,芦苇叶肉细胞超微结构的变化是该植物适应柯柯盐湖地区盐渍、低温、低气压、强辐射等环境因子的结果。     

白粉菌侵染对小麦叶片显微及超微结构的影响

通过半薄及超薄切片,比较了正常和受白粉菌感染的小麦叶片细胞的显微及超微结构的差异。观察结果发现：（1）受感染小麦叶肉细胞的细胞壁上局部沉积大量团状电子致密颗粒;（2）叶绿体形状由原来的椭圆形转变成圆形,叶绿体膜破裂;类囊体膨大,基粒片层排列疏松,同时,叶绿体内嗜饿性颗粒数量增加;（3）线粒体膜解体,内含物分散到了细胞质中。     

白粉菌侵染对小麦叶片显微及超微结构的影响白粉菌侵染对小麦叶片显微及超微结构的影响

通过半薄及超薄切片,比较了正常和受白粉菌感染的小麦叶片细胞的显微及超微结构的差异。观察结果发现(1)受感染小麦叶肉细胞的细胞壁上局部沉积大量团状电子致密颗粒;(2)叶绿体形状由原来的椭圆形转变成圆形,叶绿体膜破裂,类囊体膨大,基粒片层排列疏松,同时,叶绿体内嗜锇性颗粒数量增加;(3)线粒体膜解体,内含物分散到了细胞质中     

巨大螺旋藻光合放氧和超微结构的研究

选用常温下培养的巨大螺旋藻为材料,对其光合放氧与超微结构进行了观察和研究。结果表明：１）巨大螺旋藻具有较强的放氧能力;２）巨大螺旋藻细胞内存在有含量极丰富的类囊体,气泡,藻胆体及羧化体等特写结构与其光合放氧特性相适应;３）类囊体膜片层在细胞的部分区域已趋于重叠,且封闭成一独立系统存在,具类似真核生物叶绿体的结构;４）从进化角度来看,巨大螺旋藻类囊体膜存在的方式可以作为叶绿体系统演化的证据之一,即真     

四种生态型芦苇叶片结构的研究

采用光学显微镜和电子显微镜对４种生态型芦苇（ＰｈｒａｇｍｉｔｅｓｃｏｍｍｕｎｉｓＴｒｉｎ．）叶解剖结构及叶脉维管束鞘细胞超微结构进行了观察研究。结果表明,沼泽芦苇维管束鞘细胞内含物较少,维管束鞘细胞叶绿体呈近圆形,超微结构与典型Ｃ３植物小麦鞘细胞的相似,基粒发育退化,不含淀粉粒;沙丘芦苇鞘细胞内含物较多,鞘细胞叶绿体呈近椭圆形,超微结构与典型Ｃ４植物玉米的相似,具有不发达的基粒;重度盐化草甸芦苇鞘细胞内含物则较沼泽芦苇多,而较沙丘芦苇少,鞘细胞叶绿体形态、超微结构与沙丘芦苇相似;轻度盐化草甸芦苇鞘细胞内含物与沙丘芦苇相似,但是,其鞘细胞含有与沼泽芦苇鞘细胞内叶绿体形态相似的近圆形以及与沙丘芦苇和重度盐化草甸芦苇鞘细胞内形态相似的近椭圆形两种形态的叶绿体。表明生长在同一地区不同环境中的４种生态型芦苇的光合结构发生了深刻的变异,表现出从Ｃ３向Ｃ４进化的明显趋势。     

叶片阶段性白化小麦的叶绿体激发能分配和荧光动力学特征

叶片阶段性白化小麦是一种非常特殊的色素突变体。本文对其白色、白绿相嵌及转绿叶片的叶绿体光化活性分别进行了测定。试验表明：（１）白化和白绿相嵌叶片的叶绿体色素合成处于停滞阶段,转绿叶片则处于色素迅速合成阶段;（２）白化、白绿相嵌和转绿叶片叶绿体的激发能传递呈递增趋势;（３）三者对绿体的ＰＳⅡ活性和原初光能转化效率也呈递增趋势;（４）白化叶片叶绿体缺乏ＰＳⅠ和ＰＳⅡ外周天线色素蛋白,白绿相嵌和转绿叶片的类囊体膜多肽组分与正常叶片相近似。     

环境激素DBP对拟南芥体外培养叶片超微结构的影响

报道了酞酸酯类化合物DBP对拟南芥离体培养叶片超微结构的影响。在DBP(1.0mg·L-1)处理第3天即观察到拟南芥叶片叶绿体的超微结构受到破坏。不同浓度的DBP长期处理植株(40d)出现叶片白化、节间短缩等异常现象。在0.01mg·L-1DBP处理40d植株的叶细胞中,叶绿体出现解体,破碎部分呈颗粒状,散落其间,但细胞结构完整;0.1mg·L-1DBP处理后引起叶绿体的进一步解体,叶绿体中类囊体基粒和片层结构解体,细胞出现空洞现象,其它细胞器很少观察到;1.0mg·L-1DBP和2.0mg·L-1DBP处理植株叶片叶绿体中类囊体基粒和片层结构破碎,叶绿体结构也解体,细胞中其它细胞器数目极少。     

An ultrastructural study on gastric endocrine cells in the stomach gland patch of the koala Phascolarctos cinereus

The endocrine cells in the stomach gland patch of the koala (Phascolarctos cinereus) were studied ultrastructurally. They were classified into 3 types based on the ultrastructural profiles of their endocrine granules and tentatively categorized as type I, II, and III endocrine cells. Type I cells contained round granules that were for the most part larger than those observed in the other 2 cell types. The granules ranged from moderate to relatively high in electron density. Type II cells were angular in shape and characterized by the presence of granules that were polymorphous in profile. Contents of the endocrine granules in type II cells also showed a range of high to moderate electron density. Type III cells were oval or pyramidal in shape. They contained highly polymorphous granules that were round, oval, dumbbell-like or comma in shape and characterized by the presence of a clear space or halo separating the high to low electron-dense core from the limiting membrane of granules. Type III cells were observed most often whereas type I and II cells were a less frequent observation.     

Ultrastructural and immunohistochemical study of endocrine cells in the midgut of the cockroach Blaberus craniifer (Insecta,Dictyoptera)

Summary The midgut of Blaberus craniifer is principally made up of columnar epithelial cells which are derived from small regenerative cells found grouped in nidi. Between them, small sparsely granulated cells with clear cytoplasm can be observed lying on the basal lamina. Mainly based on the size, shape and texture of their secretory granules, at least ten types of such endocrine cells have been identified. Five cell types contain a uniform population of dense granules: (1) medium-sized, round to oval granules; (2) small elongated granules; (3) large irregular granules; (4) oval granules with a highly osmiophilic core; (5) oval, haloed granules. Five others are characterized by a heterogeneous population of granules: (6) small, round to oval, variably electron-dense granules; (7) oval medium-sized granules of variable electron density; (8) large irregular granules of variable electron density; (9) small dense granules and large vesicles with filamentous material; (10) small dense granules and very large pale vesicles.In addition, near the regenerative cells, large cells characterized by very large, irregular, dense granules (up to 4 m), lack contact with the lumen, and reach the basal lamina only by slender cytoplasmic processes.Several antisera raised against mammalian peptides and amine were used to reveal axonal fibers and endocrine cells. Serotonin-like immunoreactivity is localized in a profuse innervation of the muscle layers that surround the epithelium, whereas cholecystokinin and methionine-enkephalin antisera stain a more moderate number of axonal fibers. Cholecystokinin-, methionine-enkephalin-, substance P-, vasoactive intestinal peptide-, somatoliberin-, and gonadoliberin-like immunoreactivities were detected in endocrine cells of the epithelium. While most of the cells appear pyramidal, oval, fusiform or bowl-shaped, and seem to lack contact with the lumen, cells reaching it have been detected reacting with antisera to cholecystokinin, substance P, vasoactive intestinal peptide, somatoliberin and gonadoliberin.     

Heterogeneity of lotus rhizome starch granules as revealed by α-amylase degradation

Lotus (Nelumbo nucifera Gaertn.) rhizome starch granules have an elongated oval shape with the hilum located at one end. The morphologic characteristics were used as a direction anchor to study the heterogeneity of molecular organization of starch granules using microscopy before and after partial digestion by bacterial α-amylase (Bacillus sp.) The partially digested granule showed a single, big eroded hole at the end distant from the hilum. The enzyme-attacked end was revealed to be the loosely packed end and to be the weak point for enzyme hydrolysis. The α-amylase hydrolyzed the loosely packed central part of the granule faster than the densely packed periphery, and left an empty shell with a fish-bone-like tunnel inside. The periphery was more resistant to amylase hydrolysis and had strong birefringence. For the whole starch granule, the selectivity of α-amylase hydrolysis was low for the crystalline and amorphous regions and for amylose and amylopectin molecules. This study elucidated that the molecular organization of lotus rhizome starch granules was heterogeneous.     

高度抗寒植物冬季线粒体的电镜观察

冬季沙冬青叶肉我线粒体相当丰富,常常位于叶绿体出芽和分裂处,在质膜大量内隐形成管状细胞的附近和含有颗粒状物质、膜状物质或特殊内含和的周围也随时可见了线粒体也经常与微体和叶绿体在一起。有时甚至还不同程度地被内多所包围。沙冬青叶肉细胞中的的线粒一般灯承圆形,被膜清晰完整,嵴丰富,基质电子度较高。有时基质中有小泡或电子密度很高的颗粒和内含物,个别线粒体的基质中学有类髓样体结构。文中讨论了沙冬青线粒体的形     

Eight types of endocrine cells in the abomasum of sheep

In the ovine abomasum, 8 types of endocrine cells were classified at ultrastructural level. The gastric-type EC cells contained oval and pleomorphic granules with high electron density. The intestinal-type EC cells were filled with oval, irregular and highly dense granules. ECL cells contained irregular granules with high density and wide clear spaces. D cells were filled with round granules showing low to moderate density and finely granular matrix D1 cells contained round or oval granules with variable, low to moderate density and finely granular content. G cells showed round and oval granules with moderate density, densely packed or flocculent content. F cells were filled with oval or elliptic granules showing low density with a finely granular and flocculent matrix. X cells contained round granules with high density and homogeneous material. Gastric-type EC cells, intestinal-type EC cells, D cells, and D1 cells were represented in the cardiac, fundic and pyloric gland areas of the ovine abomasum. ECL cells and F cells were confined to the fundic glands, G cells and X cells to the pyloric glands.     

Prolactin immunoreactivity of acidophils of the small granule type

Summary The fine structure of some oval anterior pituitary cells of the adult male rats immunostained with an antiserum to rat prolactin was investigated electron microscopically on the adjacent thin sections. Their fine structural appearance is identical with that of acidophils of the small granule type (Yoshimura et al. 1974) resembling the Kurosumi-Oota LH gonadotrophs. The secretory granules of the oval cells are spherical in shape, ranging from 130 to 200 nm in diameter. Large polymorphic granules, which are generally believed to be characteristic of prolactin cells, are absent from their cytoplasm. It is concluded that the acidophil of the small granule type with a similar fine structure to the Kurosumi-Oota LH gonadotroph is a prolactin secreting cell.     

The Ultrastructure of the Endocrine Pancreas of the Grass Lizard,Mabuya quinquetaeniata*

Four endocrine cell types were identified ultrastructurally in the pancreas of the grass lizard, Mabuya quinquetaeniata. These cells were similar in shape, location and frequency to the previously described B-, A-, D- and PP-cells. The secretory granules of the B-cells were round or oval in profile, with an internal core of variable shape. The mean diameter of the B-cell granules was 780 nm (range 350–1000 nm). The A-cell granules were round, oval or irregular in shape and highly electron dense, with a narrow electron lucent space between the core and the limiting membrane. The mean diameter of these granules was 450 nm (range 200–750 nm). The D-cell granules were round, oval or irregular and of moderate electron density, with an average diameter of 340 nm (range 200–500 nm). The limiting membrane was closely apposed to the core or separated from it by a narrow lucent space. PP-cell granules were round with high electron density and with a narrow space between the core and the limiting membrane, and their average diameter was 150 nm (range 50–350 nm); these secretory granules accumulated at the cytoplasmic process. Tracing of the cytoplasmic processes of PP-cells in serially cut ultrathin sections revealed that most of these processes ended in the vicinity of blood capillaries, indicating that the PP-cells were endocrine rather than paracrine.     

Synthesis and Development of Starch Granules in High Lysine Barley Grains

Electron microscopy studies of developing endosperm have shown differences in the synthesis and development of starch granules between high lysine mutant Notch-2 and parent NP 113. The starch granules in Notch-2 were modified and did not develop into characteristic oval granules. Based on iodine absorption and phospholipids analysis, it is suggested that the presence of phospholipids impairs the development of starch granule in Notch-2. This is further confirmed by higher lipid density across starch granule in mutant Notch-2, and its absence in NP 113. Amylopectin from mutant differs from that of NP 113. The results indicate that the lack of geometry and smaller size of starch granules in Notch-2 is ultimately due to specific interaction of lipids with developing starch granules, and this leads to decreased yield.     

沙冬青叶肉细胞中一种特殊内含物的发育

用透射电镜观察了沙冬青（Ａｍ ｍ ｏｐｉｐｔａｎｔｈｕｓｍ ｏｎｇｏｌｉｃｕｓ）叶肉细胞中一种电子密度很高的近似椭圆形的特殊内含物的发育． 它始于中央液泡外侧,起初只是少量的泡状成分和电子密度很高的物质,然后两种成分逐渐增多,并随液泡膜内吞形成突起,不断伸向液泡中央,有的突起占据了液泡很大一部分体积． 接着突起中的泡状成分开始解体,电子密度很高的物质越来越多,直至充满整个突起． 当突起继续内伸时,它的尾部不断收缩变小,最后完全脱离液泡膜而游离在中央液泡里面． 这种内含物一般只出现在严冬季节,里面含有大量的脂．     

Fabrication of doughnut-shaped particles from spheroidal paramylon granules of Euglena gracilis using acetylation reaction

An anhydrous type of paramylon, the micro-sized granular storage carbohydrate (β-1,3-glucan) of Euglena, was transformed from a spheroidal to a doughnut-like shape by acetylation. Fourier transform infrared spectroscopic measurements suggested that the doughnut formation is due to removal of accessible regions of paramylon particles by acetylation of glucans. A time-course observation of the paramylon granules during acetylation by using field emission scanning electron microscopy revealed that the doughnut-making process begins with the removal of an outer membrane of the granule and that the central region of the granules is preferentially removed with the survival of a thick rim part to give the doughnut-like particles.