scholarly journals Anatomy and ultrastructure of floral nectaries of Asphodelus aestivus Brot. (Asphodelaceae)

2012 ◽  
Vol 59 (2) ◽  
pp. 29-42 ◽  
Author(s):  
Elżbieta Weryszko-Chmielewska ◽  
Thomas Sawidis ◽  
Krystyna Piotrowska
Keyword(s):  
Electron Microscopy ◽  
Large Cell ◽  
Outer Cell ◽  
Cell Nuclei ◽  
Starch Grains ◽  
Transmission Electron ◽  
Secretory Tissue ◽  
Xylem Elements ◽  
Nectariferous Tissue ◽  
Asphodelus Aestivus

The structure of septal nectaries in <i>Asphodelus aestivus</i> flowers was investigated by using light microscopy (LM), scanning electron microscopy (SEM) and transmission electron microscopy (EM). It was found that the outlets of the three parts of the nectary were situated on the ovary surface at 2/3 of its height and had the shape of elongated openings. The nectariferous tissue was in the septa of the lower part of the ovary. The secretory tissue cells formed 1-3 layers surrounding the nectary slits. They contained thin cell walls with the cuticle layer from the slit side, large cell nuclei, numerous mitochondria and plastids characterised by various shapes. In plastids, small starch grains occurred sporadically. At the beginning of anthesis, the cells were poorly vacuolized. ER cisternae and secretory vesicles were located near the outer cell wall. Fibrous substance was present in the nectary slits. In the subglandular tissue, numerous starch grains occurred at the beginning of anthesis. In this zone, cells containing raphides and xylem elements were observed. Based on the ultrastructure of the nectary it can be stated that granulocrine nectar secretion occurs in <i>A. aestivus</i>.

scholarly journals The structure of the spur nectary in Dendrobium finisterrae Schltr. (Dendrobiinae, Orchidaceae)

2012 ◽  
Vol 64 (1) ◽  
pp. 19-26 ◽  
Author(s):  
Magdalena Kamińska ◽  
Małgorzata Stpiczyńska
Keyword(s):  
Electron Microscopy ◽  
Cell Walls ◽  
Single Layer ◽  
Secretory Cells ◽  
Vascular Bundles ◽  
Nectar Guides ◽  
Floral Nectary ◽  
Transmission Electron ◽  
Secretory Tissue ◽  
The One

To date, the structure of the nectary spur of <i>Dendrobium finisterrae</i> has not been studied in detail, and the present paper compares the structural organization of the floral nectary in this species with the spurs of other taxa. The nectary spur of <i>D. finisterrae</i> was examined by means of light microscopy (LM), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). It is composed of a single layer of secretory epidermis and several layers of small and compactly arranged subepidermal secretory cells. The secretory cells have thick cellulosic cell walls with primary pits. The secretory tissue is supplied by vascular bundles that run beneath in ground parenchyma and are additionally surrounded by strands of sclerenchymatous fibers. The flowers of the investigated species displayed morphological features characteristic of bee-pollinated taxa, as they are zygomorphic, creamy-green coloured with evident nectar guides. They also emit a weak but nice scent. However, they possess some characters attributed to bird-pollinated flowers such as a short, massive nectary spur and collenchymatous secretory tissue that closely resembles the one found in the nectaries of certain species that are thought to be bird-pollinated. This similarity in anatomical organization of the nectary, regardless of geographical distribution and phylogeny, strongly indicates convergence and appears to be related to pollinator-driven selection.

scholarly journals The morphology and ultrastructure of the nectaries of marrow (Cucurbita pepo L. convar. giromontiina)

2013 ◽  
Vol 66 (3) ◽  
pp. 11-22 ◽  
Author(s):  
Marta Dmitruk ◽  
Elżbieta Weryszko-Chmielewska
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Cucurbita Pepo ◽  
Female Flower ◽  
Transmission Electron ◽  
Parenchyma Cells ◽  
Male Flowers ◽  
Nectariferous Tissue ◽  
Female Flowers ◽  
Size And Structure

The present study investigated the size and structure of the nectaries in flowers of marrow – <em>Cucurbita pepo </em>convar.<em> giromontiina </em>cv. ‘Weiser Busch’. The diameter and thickness of nectariferous layer were compared in female and male flowers of this taxon. The micromorphology as well as the anatomical and ultrastructural characters of the nectary from the female flower were observed using light, scanning and transmission electron microscopy. The density and size of stomata of the nectary epidermis from both types of flowers were examined using light microscopy. The nectaries in female flowers were found to have a larger size than in male flowers. The stomata occurring in the nectary epidermis of both types of flowers have a similar size and density. We observed that nectar was released onto the surface of the nectary not only via the stomata, but also through the walls of the epidermal cells. In TEM examination, large nuclei, different-shaped plastids, ER tubules, dictyosomes, and ribosomes were observed in the nectariferous tissue cells. A large number of mitochondria accompanying the plastids were found in the parenchyma cells of the nectary. The degradation of the nectary parenchyma cells in the flowers living for about 6 hours was asynchronous.

Cell wall differentiation during early somatic embryogenesis in plants. II. Ultrastructural study and pectin immunolocalization on chicory embryos

2000 ◽  
Vol 78 (6) ◽  
pp. 824-831 ◽  
Author(s):  
Audrey Chapman ◽  
Anne-Sophie Blervacq ◽  
Théo Hendriks ◽  
Christian Slomianny ◽  
Jacques Vasseur ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Cell Wall ◽  
Somatic Embryogenesis ◽  
Cell Walls ◽  
Ultrastructural Changes ◽  
Outer Cell ◽  
Embryogenic Cell ◽  
Transmission Electron ◽  
Outer Cell Wall

In Cichorium hybrid clone 474 (C. intybus L. var. sativum × C. endivia L. var. latifolia), direct somatic embryogenesis was induced from roots. Using transmission electron microscopy, we followed the ultrastructural changes of the outer cell wall in relation to embryo developmental stage. During the transition from an embryogenic cell to a somatic embryo, the differentiation of the outer cell wall involved both deposition and rearrangement processes. During the first divisions, the cell wall of few-celled embryos still enclosed in the root tissue appeared as a large amorphous layer of cellulose, thicker than the cell walls of the root cortex cells. When the proembryo emerged from the root cells, the outer wall surface exhibited a fibrillar material designated as the supraembryonic network. As this network disappeared, the outer cell wall changed organization, and two domains were distinguished. At the torpedo stage, the outer cell wall was more compact without any gaps and the protoderm was differentiated. Immunolocalization of an epitope recognised by JIM5 antibody revealed the unesterified nature of the supraembryonic network. Such pectins were also located at the outer third of the outer cell wall of protodermal cells as well as in the intercellular spaces. Highly methylesterified pectins recognized by JIM7 antibodies were slightly present in the cell walls during the embryogenesis process. The different stages of the outer cell wall differentiation as well as the development of the transient supraembryonic network are described, and its possible roles in somatic embryogenesis are proposed.Key words: cell differentiation, cell wall, Cichorium (chicory), pectin, somatic embryogenesis, transmission electron microscopy.

Three-dimensional culture of a pancreatic cancer cell line, SUIT-58, with air exposure can reflect the intrinsic features of the original tumor through electron microscopy

Microscopy ◽  
2020 ◽  
Author(s):  
Nobuyasu Takahashi ◽  
Fumiyo Aoyama ◽  
Akira Sawaguchi
Keyword(s):  
Electron Microscopy ◽  
Pancreatic Cancer ◽  
Transmission Electron Microscopy ◽  
Culture System ◽  
Three Dimensional ◽  
Large Cell ◽  
Air Exposure ◽  
Transmission Electron ◽  
Three Dimensional Culture

Abstract Mini-abstract: Application of a three-dimensional culture system with air exposure facilitates the formation of large cell spheres possessing cribriform glands and producing mucin in the collagen gel. Transmission electron microscopy revealed the formation of microvilli and junctional complexes at the apical side of the cell. This study aimed to reproduce the characteristics of original adenocarcinoma tumors in vitro. The pancreatic cell line, SUIT-58, derived from a moderately differentiated adenocarcinoma of metastatic pancreatic cancer was used. The cells have a sheet structure in conventional cell culture without forming glands or exhibiting mucin production in the lumen. First, the necessity of scaffolds to create an adenocarcinoma-like microenvironment for SUIT-58 pancreatic cancer cells was assessed. Compared with conventional culture plates, the use of type I collagen as a scaffold played an important role in the formation of densely congested microvilli, as observed through scanning electron microscopy. As gland formation is one of the features of adenocarcinoma, we also assessed gland formation. Use of a recently developed three-dimensional culture system with air exposure resulted in the formation of large cell spheres possessing cribriform glands, which released mucin into the lumen. Transmission electron microscopy also revealed the formation of microvilli in the lumen of the glands and junctional complex at the intercellular part, which were similar to those observed in xenografts. These findings indicate that an in vitro three-dimensional culture system with air exposure reflects the intrinsic features of the original tumor, suggesting that this culture system could be useful for preliminary research of certain cancers.

scholarly journals Early Stages of Antibacterial Damage of Metallic Nanoparticles by TEM and STEM-HAADF

2017 ◽  
Vol 14 (1) ◽  
pp. 54-61 ◽  
Author(s):  
Beatriz Liliana Espana-Sanchez ◽  
Carlos Alberto Avila-Orta ◽  
Luis Felipe Padilla-Vaca ◽  
Enrique Diaz Barriga-Castro ◽  
Florentino Soriano-Corral ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Metallic Nanoparticles ◽  
Morphological Changes ◽  
Intracellular Localization ◽  
Outer Cell ◽  
Antibacterial Mechanism ◽  
Elemental Mapping ◽  
Early Stages ◽  
Transmission Electron

Background: Propagation of pathogens has considered an important health care problem due to their resistance against conventional antibiotics. The recent challenge involves the design of functional alternatives such as nanomaterials, used as antibacterial agents. Early stages of antibacterial damage caused by metallic nanoparticles (NPs) were studied by Transmission Electron Microscopy (TEM) and combined Scanning Transmission Electron Microscopy with High Angle Annular Dark Field (STEM-HAADF), aiming to contribute to the elucidation of the primary antibacterial mechanism of metallic NPs. Methods: We analyze the NPs morphology by TEM and their antibacterial activity (AA) with different amounts of Ag and Cu NPs. Cultured P. aeruginosa were interacted with both NPs and processed by TEM imaging to determine NPs adhesion into bacteria wall. Samples were analyzed by combined STEM-HAADF to determine the NPs penetration into bacterium and elemental mapping were done. Results: Both NPs displays AA depending on NPs concentration. TEM images show NPs adhesion on bacterial cells, which produces morphological changes in the structure of the bacteria. STEMHAADF also proves the NPs adhesion and penetration by intracellular localization, detecting Ag/Cu species analyzed by elemental mapping. Moreover, the relative amount of phosphorus (P) and sulfur (S) increases slightly in P. aeruginosa with the presence of NPs. These elements are associated with damaged proteins of the outer cell membrane. Conclusions: Combined microscopy analyses suggest that the early stages of antibacterial damage caused by alteration of bacterial cell wall, and can be considered a powerful tool aiming to understand the primary antibacterial mechanism of NPs.

Mineralogy of Pb-P grains in the roots of Agrostis capillaris L. by ATEM and EXAFS

1999 ◽  
Vol 63 (6) ◽  
pp. 777-789 ◽  
Author(s):  
J. D. Cotter-Howells ◽  
P. E. Champness ◽  
J. M. Charnock
Keyword(s):  
Electron Microscopy ◽  
Heavy Metal ◽  
Physiological Role ◽  
Outer Cell ◽  
Agrostis Capillaris ◽  
Root Cells ◽  
Transmission Electron ◽  
Inactive Form ◽  
X Ray Absorption

AbstractAnalytical transmission electron microscopy (ATEM) and X-ray absorption spectroscopy (XAS) have been used to determine the mineralogy of Pb-P deposits in the roots of the heavy metal tolerant grass cultivar Agrostis capillaris L. cv. Parys Mountain. The deposits have a pyromorphite (Pb5(PO4)3Cl)-type structure and composition although some of the Cl may be substituted by OH. Energy-dispersive mapping under the scanning electron microscope demonstrated that the majority of these deposits are present in the outer cell wall of the epidermis (the outermost layer of root cells). The phosphate composition of these grains contrasts with the phytate (C6H18O24P612−) composition of Zn-P deposits observed in similar electron microscopy studies. The physiological role of heavy metal P deposits is unclear. Heavy metal P precipitates may form actively as a tolerance mechanism to heavy metals or passively, sequestering P in a metabolically inactive form.

scholarly journals Structure of trichomatous nectaries in flowers of Lonicera kamtschatica (Sevast.) Pojark.

2012 ◽  
Vol 61 (1) ◽  
pp. 13-26 ◽  
Author(s):  
Elżbieta Weryszko-Chmielewska ◽  
Małgorzata Bożek
Keyword(s):  
Electron Microscopy ◽  
Corolla Tube ◽  
Nectar Secretion ◽  
Apical Portion ◽  
Transmission Electron ◽  
Secretory Tissue ◽  
Floral Nectaries ◽  
Subcuticular Space ◽  
Lateral Walls ◽  
Scanning Electron

The structure of the floral nectaries of <i>Lonicera kamtschatica</i> was examined using light microscopy, scanning electron microscopy and transmission electron microscopy. Nectariferous tissues are located in the lower portion of the corolla tube. It was found that the secretory tissue of the nectary was composed of two layers of epidermal formations: short papillae and about 3x longer unicellular trichomes. They cover the adaxial surface of a small spur. Nectar secretion takes place through the apical portion of the trichomes and papillae. The cell wall of the upper part of the trichome has protuberances participating in nectar transfer to the subcuticular space which reaches large dimensions. The lateral walls of the trichomes are saturated with cutin. The papillae have much thicker walls than the trichomes. In the papillae, there are no wall protuberances. Less secretion accumulates in the subcuticular cavities of the papillae than in the trichomes.

Young plastids in shoot apical cells of a genetic albino strain of Nicotiana (Solanaceae)

1977 ◽  
Vol 55 (10) ◽  
pp. 1429-1433 ◽  
Author(s):  
Anne A. Susalla ◽  
Paul G. Mahlberg
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Shoot Apex ◽  
Prolamellar Body ◽  
Starch Grains ◽  
Prolamellar Bodies ◽  
Plastid Envelope ◽  
Transmission Electron ◽  
Peripheral Areas ◽  
Albino Strain

The ultrastructure of young plastids in shoot apices of a genetic albino strain of Nicotiana was examined by transmission electron microscopy. Typical young plastids were variable in shape and contained prolamellar bodies in various stages of organization. Thylakoids were few in number, some originating from the prolamellar body while others appeared free in the densely ribosomal stroma. Peripheral areas of the young plastids contained electron-transparent vesicles and tubules which were either in proximity or connected to the inner plastid envelope. Osmiophilic globules occasionally occurred in association with prolamellar bodies. Relatively large starch grains were common; cytoplasmic invaginations into the plastids were less common. Young plastids in the genetic green shoot apex closely resembled those of the genetic albino. These results indicate that organization of large-type grana in plastids of mature phenotypically green, genetic albino leaves occurs beyond the apex stage of germinated seedlings of this strain of Nicotiana.

scholarly journals The structure of the ovary epidermis emitting odorous compounds in Allium karataviense Regel

2014 ◽  
Vol 66 (4) ◽  
pp. 15-24
Author(s):  
Beata Żuraw ◽  
Elżbieta Weryszko-Chmielewska ◽  
Halina Laskowska ◽  
Elżbieta Pogroszewska
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Essential Oils ◽  
Neutral Lipids ◽  
Outer Wall ◽  
Large Cell ◽  
Cell Nuclei ◽  
Histochemical Tests ◽  
Odorous Compounds ◽  
Scanning Electron

Many plants develop in the petal epidermis papillae emitting essential oils. In species of the genus <em>Allium</em>, papillae occur in the ovary epidermis. The aim of this study was to determine the structure of papillae in <em>Allium karataviense </em>Regel and to perform histochemical tests that would allow the components of their secretion to be investigated, mainly the presence of essential oils. Examination was performed using light and scanning electron microscopy. It was found that in conical papillae, with a height of about 83 μm, there were large cell nuclei, a thick outer wall with a layer of striated cuticle, and a varying degree of cell vacuolation, depending on the age of the ovary. Using histochemical reactions, we demonstrated neutral lipids, acid lipids and pectins to occur in the papillae. Neutral lipids are characteristic of essential oils.

Techniques for Transmission Electron Microscopy of Fiber-Matrix Interfaces in Aluminum Alloy-Boron Composites by Ion Erosio

1971 ◽  
Vol 29 ◽  
pp. 204-205
Author(s):  
G. G. Shaw
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Aluminum Alloy ◽  
Electron Beam ◽  
Pure Aluminum ◽  
Ion Milling ◽  
Transmission Electron ◽  
Fiber Matrix ◽  
Ion Erosion ◽  
Row Of Fibers

The morphology and composition of the fiber-matrix interface can best be studied by transmission electron microscopy and electron diffraction. For some composites satisfactory samples can be prepared by electropolishing. For others such as aluminum alloy-boron composites ion erosion is necessary.When one wishes to examine a specimen with the electron beam perpendicular to the fiber, preparation is as follows: A 1/8 in. disk is cut from the sample with a cylindrical tool by spark machining. Thin slices, 5 mils thick, containing one row of fibers, are then, spark-machined from the disk. After spark machining, the slice is carefully polished with diamond paste until the row of fibers is exposed on each side, as shown in Figure 1.In the case where examination is desired with the electron beam parallel to the fiber, preparation is as follows: Experimental composites are usually 50 mils or less in thickness so an auxiliary holder is necessary during ion milling and for easy transfer to the electron microscope. This holder is pure aluminum sheet, 3 mils thick.

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