Applications of Environmental Scanning Electron Microscopy (ESEM) in botanical research

Abstract

Conventional Scanning Electron Microscopy (SEM) is limited by artefacts from sample preparation, while Environmental Scanning Electron Microscopy (ESEM) permits observations of hydrated, non-conductive samples without any preparation. In this short review, the two systems are described and some examples given. In addition, a study of trace element localization by X-ray ESEM microanalysis in Azolla caroliniana cultured in the presence of trace elements is presented. The highest concentration occurred in roots and stem. Leaves showed lower accumulation, with concentrations decreasing from the base to the apex of the shoot, and sharp differences between ventral and dorsal lobes of single leaves, the former accumulating more than the latter. The epidermal cells in the ventral lobes of basal leaves were largely lost in treated plants. The differential localisation of trace elements in the plant protected the dorsal lobes, which are the main photosynthetic part of the plant, the nitrogen-fixing cyanobacterial colonies and the apical meristems from potentially adverse effects of trace elements.     

Studies of Small-intestinal Mucosa with the Scanning Electron Microscope

Preliminary observations indicate that scanning electron microscopy is a useful method for studying the surface of the small intestine.     

Scanning Electron Microscope Study of Neisseria gonorrhoeae

Morphological studies utilizing various microscopy techniques have aided in our understanding of the gonococcus and gonorrhea. In this study scanning electron microscopy was used to study differences in virulent (colony types 1 and 2) and avirulent (colony types 3 and 4) gonococci relative to colony appearance, patterns of growth in liquid media, and surface features of individual cocci. Colony types of virulent gonococci are smaller in diameter but have a higher evaluation than those of avirulent mutants. Colony type 2 has a convex undersurface that is associated with surface pitting of solid media. When the colonies are grown in liquid media, various degrees of autoagglutination are observed; this is most pronounced with type 2 and least evident with type 4. Although pili may be involved in this phenomena, other mechanisms must be employed, since type 3 gonococci that lack pili autoagglutinate. Pili are seen on types 1 and 2 and are absent from types 3 and 4. They appear as individual threads radiating from the bacteria or as bundles of pili attaching adjacent cocci. Another extracellular structure consists of small spherical bodies that can coat the bacteria surface, attach to pili, or exist free from other bacterial components. These spheres are least evident with type 4. The gonococcal surface is pebbly with multiple sulci.     

紫彩血蛤外套膜的扫描电镜观察

用扫描电镜观察了紫彩血蛤外套膜的表面结构。其内表皮表面具板块状结构 ,沟内和嵴上均有簇生的纤毛丛 ,沟内纤毛丛较多 ;纤毛长约 9μm ,直径约 0 2 μm ,每一纤毛末端具一约 1 μm× 0 6 5 μm的勺状膨大 ;内表皮表面还具丰富的微绒毛和分泌泡。外表皮表面也略呈板块状 ,并有大量分泌泡。     

Transmission And Scanning Electron Microscope Preparations Of The Same Cell Culture

A technique has been developed which allows transmission electron microscopy and scanning electron microscopy to be performed on the same cell culture sample. The technique uses the Costar 3393 Leighton Tube containing a plastic insert, which does not stick to epoxy, for transmission electron microscopy. A cut piece of the plastic insert can be critical point dried, sputter coated and viewed under high vacuum with the scanning electron microscope.     

Graft Formation in Sitka Spruce: A Scanning Electron Microscope Study

Low-temperature and conventional scanning electron microscopyhave been used to examine the callus formed at the graft interfacein Picea sitchensis (Bong.) Carr. Callus cells are producedby both cambium and ray parenchyma dedifferentiation and redifferentiationin scion and stock. Adhesion between the cells derived fromscion and rootstock is thought to be my means of pectinaceousbeads at the surface of the callus cells, preceding a more generalfusion of cell walls. The cambia of the two graft componentsare prevented from growing towards each other by the presenceof callus. Instead, the differentiation of new cambium withinthe callus, in the vicinity of the cambia exposed at the preparedsurfaces of the scion and rootstock, links them to form a continuouscambial layer around the combined stem. Callus, cambium, differentiation, grafting, Picea sitchensis     

Scanning Electron Microscope Observations of Amoeba proteus During Phagocytosis*

SYNOPSIS. Phagocytosing Amoeba proteus at different stages of forming foodcups have been observed by scanning electron microscopy. A nonphagocytosing ameba is characterized by dorsal and lateral ridges running longitudinally over the posterior half of the cell and its attachment to the substrate over small areas. When stimulated by prey organisms, the ameba loses polarity and ridges, and adheres to the substrate more firmly over a wider area of contact. Then it forms broad pseudopods to surround its prey and this results in the formation of foodcups. The surface of all amebae is covered with small projections, and membranous blebs are often seen on the surface of phagocytosing organisms.     

犬科动物针毛结构的扫描电镜观察

运用扫描电镜技术对4种犬科动物针毛的结构进行观察,发现4种犬科动物在针毛鳞片结构上具有明显区别,提示利用毛鳞片的类型和排列规律作犬科动物种类鉴别是一种可行的方法.此法在法医物证检验方面的应用需要建立野生动物毛样数据库及先进的图像处理系统来完善.     

A Scanning Electron Microscope Study of Theobroma cacao Somatic Embryogenesis

This study describes the somatic embryogenesis of Theobromacacao L. with a scanning electron microscope. It revealed earlydevelopmental stages as globular and incipient heart-shaped.Morphological abnormalities, such as the occurrence of threeand four cotyledons and round or long forms of embryoids witha long and thin or short and thick stalk-like structure whichseems to equate to a suspensor, were also observed. A suspensorwas found in some embryoids. cacao, Theobroma cacao, embryoids, somatic embryogenesis, SEM     

蝗虫(直翅目:蝗总科)口器感受器的扫描电镜观察

对蝗总科8种蝗虫的口器感受器的超微结构、类型和分布进行了观察分析,共观察到6种蝗虫口器感受器:毛形感受器、锥形感受器、腔锥形感受器、B(o)hm氏鬃毛、刺形感受器I和刺形感受器Ⅱ,其中B(o)hm氏鬃毛是首次报道.同时对观察到的3种角质齿进行了描述.     

Scanning Electron Microscope Observation on the Pollen Grains of Chenopodiaceae

Pollen grains of 50 Chenopodiaceae species were observed under SEM and distincted into 5 morphological types, 6 subtypes. This work suggest that the Chenopodiaceae pollen is distinctable at substructural level.     

Scanning Electron Microscope Studies of Steinernema anomali Kozodoi, 1984

This paper presents SEM micrographs of portions of the male, female, and infective-stage juvenile of Steinernema anomali. Included are micrographs of the cephalic and caudal region, spicules, and gubernaculum of the male, the cephalic and vulval region of the female, and the cephalic region of the infective-stage juvenile. Males have six labial and four prominent cephalic papillae and small amphids. There are 11-14 pairs and one single genital papillae; of these, 6-9 pairs are preanal and subventral, one pair preanal, lateral, one pair adanal, and three pairs postanal. Spicules have a short head, a long blade, and a reduced shaft. The distal end is enlarged and bears a dorsal aperture. Gubernaculum much shorter than spicules; cuneus of gubernaculum short and bifurcate anteriorly. Females have six labial and four cephalic papillae and small amphids. Vulva with a thickened posterior lip. Infective juveniles have a smooth head, prominent amphids, and four cephalic papillae. Labial papillae, if present, are not evident.     

Scanning Electron Microscope Study of Bacteria Associated with the Rumen Epithelium of Sheep

Examination of the rumen epithelium of sheep by scanning electron microscopy revealed bacteria associated with the epithelial surface. Comparison of epithelial surfaces from 10 sheep revealed areas that were consistently densely covered with bacteria and other areas where the cover was consistently light. The bacterial populations were frequently of mixed morphological types, but areas populated with a single type were also observed. This finding, together with the discovery of bacterial forms not previously described in rumen contents, suggests that a specific flora may exist on the rumen epithelial surface. The functional significance of such a population is discussed.     

Some Observations of Ascospores of Neurospora crassa Made with a Scanning Electron Microscope

Scanning electron micrographs of ascospores of Neurospora crassa reveal two of the structures which develop during germination and outgrowth: (i) a germination pore and (ii) the probable site of initiation of hyphal cell wall synthesis.     

印度块菌子囊果内部解剖结构的扫描电镜观察

利用扫描电镜对成熟印度块菌子囊果的内部结构进行了观察,以系统揭示其子囊果内部组织特征,为块菌属的分类以及块菌属真菌子囊果的生理研究奠定基础。观察结果进一步证明,成熟印度块菌子囊果横切面上的白色迷宫状脉络是由不育的侧丝构成,而暗脉则是被侧丝缠绕并包裹着的可育的菌丝组织,即产孢组织,这些白色脉络和暗脉就构成了印度块菌子囊果横切面上迷宫状的纹脉;产孢组织中,可观察到正在发育的大大小小的子囊被缠绕在一起的大量产囊丝与侧丝包裹着,形成密密麻麻微小的类似蜂巢状结构;子囊孢子游离于子囊中,成熟子囊孢子表面有刺状纹饰,刺的顶端有小弯钩。单个子囊内含的子囊孢子大小与其内含的子囊孢子数目有关,子囊内所含的子囊孢子越多,子囊孢子就越小。     

Use of the Scanning Electron Microscope for Viewing Bacteria in Soil

Scanning electron microscopy was used for viewing Bacillus cereus and Staphylococcus aureus in three different soils. Both organisms were detected in the test soils at an approximate concentration of 10⁷ cells per gram of soil; theoretically, the minimal number of microorganisms required for detection with the scanning electron microscope technique was between 10⁷ and 10¹⁰ cells per gram of soil. Because the concentration of cells was critical, the use of scanning electron microscopy as an extraterrestrial life detection instrument would be limited with soils containing more than 10⁷ bacteria per gram of soil.