scholarly journals Micromorphology of the epidermis of the floral nectary of Rhododendron japonicum (A. Gray) J. V. Suringar ex E.H. Wilson.

2012 ◽  
Vol 60 (1) ◽  
pp. 45-53 ◽  
Author(s):  
Elżbieta Weryszko-Chmielewska ◽  
Mirosława Chwil
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Growth Stages ◽  
Mosaic Pattern ◽  
Floral Nectary ◽  
Half Height ◽  
Floral Nectaries ◽  
Small Clusters ◽  
Different Growth Stages ◽  
Scanning Electron

The conducted study related to the structure of the floral nectaries of <i>Rhododendron japonicum</i> (A. Gray) J. V. Suringar ex E. H. Wilson. The structure of the secretory epidermis of the nectaries was analysed by using scanning electron microscopy (SEM). <i>Rhododendron japonicum</i> develops the superior pistil with a 5-loculed ovary equipped in five ribs. The nectary gland is located in the lower part of the ovary. In the nectary regions located on the extension of the ribs of the ovary, stomata were very numerous. In the upper part of the nectary, stomata were arranged individually or in small clusters, whereas at its half- -height they formed stomatal areas. The stomata were at different growth stages. They were arranged in different directions. The stomata developed on the nectary surface according to the mosaic pattern. The stomata from the lower situated part of the nectary had a different structure than those occurring in the upper half of the nectary. The stomata in the nectaries of <i>Rh. japonicum</i> belong to the actinocytic type. The cuticle layer in the upper part of the nectary was better developed and had a characteristic sculpture, whereas in the lower part it was smooth.

scholarly journals Comparison of features of the epidermis and the size of the floral nectary in four species of the genus Cotoneaster Med.

2012 ◽  
Vol 64 (4) ◽  
pp. 47-58 ◽  
Author(s):  
Mirosława Chwil ◽  
Elżbieta Weryszko-Chmielewska
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Stomatal Density ◽  
Epidermal Cells ◽  
Floral Nectary ◽  
Cuticular Ornamentation ◽  
Floral Nectaries ◽  
Nectariferous Tissue ◽  
Nectar Flow ◽  
Scanning Electron

The investigations involved four species of the <i>Cotoneaster</i> genus: <i>C. divaricatus</i>, <i>C. horizontalis</i>, <i>C. lucidus</i>, <i>C. praecox</i>, which are commonly grown for decorative purposes. In Poland, these plants bloom in May and June and are a source of abundant spring nectar flow for insects. The floral nectaries of the above-mentioned species were examined using stereoscopic, light, and scanning electron microscopy in order to assess their size and epidermal microstructure. In the plants studied, the upper part of the hypanthium is lined by nectariferous tissue. The nectaries in the four species vary in terms of their sizes. Nectar is secreted onto the surface of the epidermis through anomocytic, slightly elongated or circular stomata. The largest stomata on the nectary epidermis were found in the flowers of <i>C. horizontalis</i>, and the smallest ones in <i>C. divaricatus</i>.Their size and location in relation to other epidermal cells were taxon-specific. The highest density of stomata in the nectary epidermis was found in <i>C. divaricatus</i> (205 per mm<sup>2</sup>), whereas <i>C. horizontalis</i> flowers exhibited the lowest (98 per mm<sup>2</sup>) stomatal density. The cuticular ornamentation on the nectary epidermis surface was diverse. The stomatal indices calculated for the nectary epidermis were considerably lower than for the leaves in the particular species.

scholarly journals Characteristics of the surface of the epidermis in floral nectaries and the receptacle of mountain ash (Sorbus aucuparia L.)

2012 ◽  
Vol 60 (2) ◽  
pp. 23-30
Author(s):  
Agata Konarska
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Outer Surface ◽  
Flower Development ◽  
Epidermal Cells ◽  
Sorbus Aucuparia ◽  
Mountain Ash ◽  
Floral Nectaries ◽  
Scanning Electron

The structure of receptacular surfaces of floral nectaries at two flowering stages and the structure of the outer surface of the receptacle of <i>Sorbus aucuparia</i> were investigated using scanning electron microscopy. Changes in the development of the cuticular epithelium of the nectary epidermis and differences in the degree of aperture of stomata were observed. Increased undulation of the gland surface was found during flower development. Numerous stomata were situated slightly below the level of epidermal cells of the nectary. At the pollination stage, open pores or pores surrounded by the cuticular epithelium were observed, as well as covered by dried secretion. Dried nectar in the form of patches was also visible on the surface of the gland. Stomata of the outer surface of the receptacle were located on protrusions and surrounded by the cuticular epithelium.

scholarly journals Structure of nectaries of Malus sylvestris (L.) Mill.

2012 ◽  
Vol 59 (1) ◽  
pp. 41-48
Author(s):  
Agata Konarska
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Middle Part ◽  
Epidermal Cells ◽  
Secretory Cells ◽  
Floral Nectary ◽  
Malus Sylvestris ◽  
Parenchyma Cells ◽  
Nectariferous Tissue ◽  
Scanning Electron

The structure of floral nectary of <i>Malus sylvestris</i> was examined using light and scanning electron microscopy. Nectaries in <i>M. sylvestris</i> flowers were situated on the adaxial surface of the receptacle, between the style and the base of filaments. The middle part of the nectary was covered epidermal cells with striated cuticle. The remaining part of the nectary was covered with smooth cuticle. Open and modified nectarostomata were situated at the same level as epidermal cells. The nectariferous tissue was formed by densely packed small parenchyma cells (secretory cells) with dark protoplasts.

scholarly journals Growth of Nacre Biocrystals by Self-Assembly of Aragonite Nanoparticles with Novel Subhedral Morphology

Crystals ◽  
2019 ◽  
Vol 10 (1) ◽  
pp. 3
Author(s):  
Ruohe Gao ◽  
Rize Wang ◽  
Xin Feng ◽  
Gangsheng Zhang
Keyword(s):  
Electron Microscopy ◽  
Self Assembly ◽  
The Self ◽  
Growth Stages ◽  
Research Model ◽  
Biomimetic Materials ◽  
Transmission Electron ◽  
Nanoparticle Morphology ◽  
Different Growth Stages ◽  
Scanning Electron

Nacre has long served as a research model in the field of biomineralization and biomimetic materials. It is widely accepted that its basic components, aragonite biocrystals, namely, tablets, are formed by the nanoparticle-attachment pathway. However, the details of the nanoparticle morphology and arrangement in the tablets are still a matter of debate. Here, using field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM), we observed the nanostructure of the growing tablets at different growth stages and found that: (1) the first detectable tablet looked like a rod; (2) tablets consisted of subhedral nanoparticles (i.e., partly bounded by crystal facets and partly by irregular non-crystal facets) that were made of aragonite single crystals with a width of 160–180 nm; and (3) these nanoparticles were ordered in orientation but disordered in position, resulting in unique subhedral and jigsaw-like patterns from the top and side views, respectively. In short, we directly observed the growth of nacre biocrystals by the self-assembly of aragonite nanoparticles with a novel subhedral morphology.

scholarly journals The position and structure of the nectary in spring heath (Erica carnea L.) flowers

2012 ◽  
Vol 62 (2) ◽  
pp. 13-21 ◽  
Author(s):  
Elżbieta Weryszko-Chmielewska ◽  
Mirosław Chwil ◽  
Marek Wróbel
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Guard Cells ◽  
Small Degree ◽  
Nectar Secretion ◽  
Ecological Traits ◽  
Anomocytic Stomata ◽  
Pore Opening ◽  
Floral Nectaries ◽  
Scanning Electron

Ecological traits of <i>Erica carnea</i> L. flowers and the morphology of floral nectaries were investigated using stereoscopic, light and scanning electron microscopy. The nectary in the flowers of <i>Erica carnea</i> is located in the basal part of the ovary. It represents the gynoecial nectary type. It has the form of a yellow, ribbed ring with eight outgrowths, pointed towards the base, which alternately adjoin the stamen filaments. The height of the nectary is 400 µm and its thickness 200 - 250 µm. The parenchyma of the nectary is composed of 6 - 8 layers. Nectar secretion occurs through anomocytic stomata with a diameter of 17 µm. Guard cells are only found on the outgrowths of the nectary and they are situated most frequently at the level of other epidermal cells. During nectar secretion, a small degree of pore opening was observed. In the flowers of <i>Erica carnea</i>, secondary nectar presentation was found, with the nectar accumulating at the base of the fused corolla.

Pathogenesis of Human Hair Defects

1974 ◽  
Vol 32 ◽  
pp. 12-13
Author(s):  
P.S. Porter ◽  
T. Aoyagi ◽  
R. Matta
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Human Hair ◽  
Standard Techniques ◽  
Scanning Electron

Using standard techniques of scanning electron microscopy (SEM), over 1000 human hair defects have been studied. In several of the defects, the pathogenesis of the abnormality has been clarified using these techniques. It is the purpose of this paper to present several distinct morphologic abnormalities of hair and to discuss their pathogenesis as elucidated through techniques of scanning electron microscopy.

Ultrastructural Analysis of the Salivary Glands of Gromphadorhina Portentosa (Schaum)

1977 ◽  
Vol 35 ◽  
pp. 638-639
Author(s):  
P.J. Dailey
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Salivary Glands ◽  
Secretory Vesicles ◽  
The Past ◽  
Transmission Electron ◽  
Means Of Transmission ◽  
Gromphadorhina Portentosa ◽  
Scanning Electron ◽  
Topographical Relief

The structure of insect salivary glands has been extensively investigated during the past decade; however, none have attempted scanning electron microscopy (SEM) in ultrastructural examinations of these secretory organs. This study correlates fine structure by means of SEM cryofractography with that of thin-sectioned epoxy embedded material observed by means of transmission electron microscopy (TEM).Salivary glands of Gromphadorhina portentosa were excised and immediately submerged in cold (4°C) paraformaldehyde-glutaraldehyde fixative1 for 2 hr, washed and post-fixed in 1 per cent 0s04 in phosphosphate buffer (4°C for 2 hr). After ethanolic dehydration half of the samples were embedded in Epon 812 for TEM and half cryofractured and subsequently critical point dried for SEM. Dried specimens were mounted on aluminum stubs and coated with approximately 150 Å of gold in a cold sputtering apparatus.Figure 1 shows a cryofractured plane through a salivary acinus revealing topographical relief of secretory vesicles.

Two- or three-way observations of the identical cell elements within the same sections by LM, TEM and/or SEM

1978 ◽  
Vol 36 (2) ◽  
pp. 82-83 ◽  
Author(s):  
Nakazo Watari ◽  
Yasuaki Hotta ◽  
Yoshio Mabuchi
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Fine Structure ◽  
Light Microscopy ◽  
Thin Sections ◽  
Transmission Electron ◽  
Identical Cell ◽  
Electron Microscopes ◽  
Scanning Electron

It is very useful if we can observe the identical cell elements within the same sections by light microscopy (LM), transmission electron microscopy (TEM) and/or scanning electron microscopy (SEM) sequentially, because, the cell fine structure can not be indicated by LM, while the color is; on the other hand, the cell fine structure can be very easily observed by EM, although its color properties may not. However, there is one problem in that LM requires thick sections of over 1 μm, while EM needs very thin sections of under 100 nm. Recently, we have developed a new method to observe the same cell elements within the same plastic sections using both light and transmission (conventional or high-voltage) electron microscopes.In this paper, we have developed two new observation methods for the identical cell elements within the same sections, both plastic-embedded and paraffin-embedded, using light microscopy, transmission electron microscopy and/or scanning electron microscopy (Fig. 1).

Spontaneous Cataract in Nude Athymic Mice

1977 ◽  
Vol 35 ◽  
pp. 512-513
Author(s):  
Ronald H. Bradley ◽  
R. S. Berk ◽  
L. D. Hazlett
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Nude Mouse ◽  
Cellular Immunity ◽  
Phosphate Buffer ◽  
Osmium Tetroxide ◽  
Athymic Mice ◽  
Transmission Microscopy ◽  
Mouse Lens ◽  
Scanning Electron

The nude mouse is a hairless mutant (homozygous for the mutation nude, nu/nu), which is born lacking a thymus and possesses a severe defect in cellular immunity. Spontaneous unilateral cataractous lesions were noted (during ocular examination using a stereomicroscope at 40X) in 14 of a series of 60 animals (20%). This transmission and scanning microscopic study characterizes the morphology of this cataract and contrasts these data with normal nude mouse lens.All animals were sacrificed by an ether overdose. Eyes were enucleated and immersed in a mixed fixative (1% osmium tetroxide and 6% glutaraldehyde in Sorenson's phosphate buffer pH 7.4 at 0-4°C) for 3 hours, dehydrated in graded ethanols and embedded in Epon-Araldite for transmission microscopy. Specimens for scanning electron microscopy were fixed similarly, dehydrated in graded ethanols, then to graded changes of Freon 113 and ethanol to 100% Freon 113 and critically point dried in a Bomar critical point dryer using Freon 13 as the transition fluid.

Scanning and Transmission Microscopy of Nematocyst Batteries in Epitheliomuscular Cells of Hydra

1971 ◽  
Vol 29 ◽  
pp. 410-411 ◽  
Author(s):  
Jane A. Westfall ◽  
S. Yamataka ◽  
Paul D. Enos
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Osmium Tetroxide ◽  
External Surface ◽  
Three Dimensional ◽  
Surface Structures ◽  
Transmission Microscopy ◽  
Transmission Electron ◽  
Freeze Dried ◽  
Scanning Electron

Scanning electron microscopy (SEM) provides three dimensional details of external surface structures and supplements ultrastructural information provided by transmission electron microscopy (TEM). Animals composed of watery jellylike tissues such as hydras and other coelenterates have not been considered suitable for SEM studies because of the difficulty in preserving such organisms in a normal state. This study demonstrates 1) the successful use of SEM on such tissue, and 2) the unique arrangement of batteries of nematocysts within large epitheliomuscular cells on tentacles of Hydra littoralis.Whole specimens of Hydra were prepared for SEM (Figs. 1 and 2) by the fix, freeze-dry, coat technique of Small and Màrszalek. The specimens were fixed in osmium tetroxide and mercuric chloride, freeze-dried in vacuo on a prechilled 1 Kg brass block, and coated with gold-palladium. Tissues for TEM (Figs. 3 and 4) were fixed in glutaraldehyde followed by osmium tetroxide. Scanning micrographs were taken on a Cambridge Stereoscan Mark II A microscope at 10 KV and transmission micrographs were taken on an RCA EMU 3G microscope (Fig. 3) or on a Hitachi HU 11B microscope (Fig. 4).

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