scholarly journals Comparative structure of the osmophores in the flowers of Stanhopea graveolens Lindley and Cycnoches chlorochilon Klotzsch (Orchidaceae)

2012 ◽  
Vol 65 (2) ◽  
pp. 11-22 ◽  
Author(s):  
Sebastian Antoń ◽  
Magdalena Kamińska ◽  
Małgorzata Stpiczyńska
Keyword(s):  
Electron Microscopy ◽  
Cell Walls ◽  
Lipid Droplets ◽  
Secretory Cells ◽  
Vascular Bundles ◽  
Scent Glands ◽  
Euglossine Bees ◽  
Dense Cytoplasm ◽  
Transmission Electron ◽  
Comparative Structure

The structure of the osmophores in <i>Stanhopea graveolens</i> and <i>Cycnoches chlorochilon</i> was studied by means of light microscopy (LM), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The scent glands are located in the basal part of the labellum. The surface of the osmophores is wrinkled or rugose, which increases the area of fragrance emission. On the surface of the epidermis, remnants of secretion are noticeable in <i>S. graveolens</i>, but these are absent in <i>C. chlorochilon</i>. The osmophore tissue is composed of secretory epidermal cells and several layers of subepidermal parenchyma, and it is supplied by vascular bundles that run in ground parenchyma. The secretory cells have large nuclei, a dense cytoplasm with numerous ER profiles, lipid droplets, and plastids with a substantial amount of starch, which are probably involved in the synthesis of volatile substances. In the cell walls of the osmophore cells, numerous pits with plasmodesmata occur that are likely to take part in symplastic transport of the scent compounds. The structure of the osmophores is similar in both investigated species. Both <i>S. graveolens</i> and <i>C. chlorochilon</i> are pollinated by euglossine bees, and such similarity results from adaptation to effective scent emission and attraction of pollinators.

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.

Light and transmission electron microscopy of English oak ectomycorrhizal short roots

1984 ◽  
Vol 62 (7) ◽  
pp. 1327-1335 ◽  
Author(s):  
H. H. Edwards ◽  
R. V. Gessner
Keyword(s):  
Electron Microscopy ◽  
Cell Walls ◽  
Quercus Robur ◽  
Lipid Droplets ◽  
Apical Meristem ◽  
Fungal Symbiont ◽  
Host Root ◽  
Transmission Electron ◽  
Cell Layers ◽  
English Oak

The incorporation of caffeine in standard transmission electron microscope fixation procedures has allowed good preservation and embedment of ectomycorrhizal short roots of English oak (Quercus robur L.). In the mantle the most conspicuous structures are cystidia which radiate outwards from the surface. These conically shaped cells have knobs at their tips and thickened cell walls. The cystidia and other outer mantle cells contain many cytoplasmic constituents, whereas the inner mantle cells are nearly devoid of cytoplasm. The mantle cells are held together by an intercellular slime network. The Hartig net cells are filled with cytoplasm and contain numerous lipid droplets. Typical dolipore septa separate the cells; however, these cells have irregularly branched shapes. The host root tissue appears little altered by the presence of the fungal symbiont. However, the root cap consists of only a few cell layers. The apical meristem is functional as evidenced by the presence of newly divided cells and microtubules lining enlarging cells.

Ultrastructural studies of the relationship between actin filaments and secretory granules

1990 ◽  
Vol 48 (3) ◽  
pp. 458-459
Author(s):  
Ellen Holm Nielsen
Keyword(s):  
Electron Microscopy ◽  
Colloidal Gold ◽  
Actin Filaments ◽  
Secretory Granules ◽  
Secretory Cells ◽  
Ultrastructural Studies ◽  
Transmission Electron ◽  
Granule Membrane ◽  
Ultrathin Sections ◽  
Lowicryl K4m

In secretory cells a dense and complex network of actin filaments is seen in the subplasmalemmal space attached to the cell membrane. During exocytosis this network is undergoing a rearrangement facilitating access of granules to plasma membrane in order that fusion of the membranes can take place. A filamentous network related to secretory granules has been reported, but its structural organization and composition have not been examined, although this network may be important for exocytosis.Samples of peritoneal mast cells were frozen at -70°C and thawed at 4°C in order to rupture the cells in such a gentle way that the granule membrane is still intact. Unruptured and ruptured cells were fixed in 2% paraformaldehyde and 0.075% glutaraldehyde, dehydrated in ethanol. For TEM (transmission electron microscopy) cells were embedded in Lowicryl K4M at -35°C and for SEM (scanning electron microscopy) they were placed on copper blocks, critical point dried and coated. For immunoelectron microscopy ultrathin sections were incubated with monoclonal anti-actin and colloidal gold labelled IgM. Ruptured cells were also placed on cover glasses, prefixed, and incubated with anti-actin and colloidal gold labelled IgM.

Paracrystalline bundles of large tubules, induced in vitro by Mebendazole in Cysticercus cellulosae

Parasitology ◽  
1981 ◽  
Vol 83 (3) ◽  
pp. 513-518 ◽  
Author(s):  
J. P. Laclette ◽  
Marie Therese Merchant ◽  
Kaethe Willms ◽  
L. Cañedo
Keyword(s):  
Electron Microscopy ◽  
Culture Medium ◽  
Morphological Changes ◽  
Bladder Wall ◽  
Secretory Cells ◽  
External Diameter ◽  
Nematode Larvae ◽  
Transmission Electron ◽  
Cysticercus Cellulosae

SUMMARYThe effect of the anthelmintic Mebendazole on Cysticercus cellulosae maintained in culture medium was studied by transmission electron microscopy. In addition to the well-known morphological changes induced by Mebendazole in other cestode and nematode larvae, it also induced the cytoplasmic appearance of paracrystalline bundles in the secretory cells of the bladder wall. These bundles were formed by groups of large parallel tubules arranged in a hexagonal-like pattern. The tubules, which had an external diameter of about 50 nm and a length that might exceed 5 μm, were surrounded by a matrix and a distance between neighbouring tubules of 80–120 nm centre to centre was estimated. The tubules were stable to colchicine and low temperature. The temporary appearance of bundles is described and some alternative explanations on their origin are advanced.

Regenerated Middle Ear Mucosa after Tympanoplasty. Part I. Transmission Electron Microscopy

1986 ◽  
Vol 94 (3) ◽  
pp. 339-343 ◽  
Author(s):  
Roberto Gamoletti ◽  
Paola Poggi ◽  
Mario Sanna ◽  
Carlo Zini
Keyword(s):  
Electron Microscopy ◽  
Middle Ear ◽  
Goblet Cells ◽  
Secretory Cells ◽  
Canal Wall ◽  
Ciliated Cells ◽  
Middle Ear Mucosa ◽  
Morphologic Characteristics ◽  
Transmission Electron ◽  
Ultrastructural Appearance

The ultrastructural appearance of the regenerated middle ear mucosa—found at the second operation of staged intact canal wall tympanoplasty (ICWT) with mastoidectomy—has been evaluated with the transmission electron microscope. The regenerated epithelium showed all the morphologic characteristics of the normal middle ear mucosa: ciliated cells, noncillated cells, and secretory cells. All of these (Including goblet cells) have been found in the specimens. It is concluded that a normal middle ear mucosa regenerates to cover all denuded bone surfaces after the first operation of staged ICWT with mastoidectomy, when silicone rubber sheeting has been used to prevent adhesions and maintain an air-containing middle ear space.

Colonization of Sphagnum cells by Lyophyllum palustre

1985 ◽  
Vol 63 (4) ◽  
pp. 757-761 ◽  
Author(s):  
E. Untiedt ◽  
K. Müller
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Light Microscopy ◽  
Host Cell ◽  
Cell Walls ◽  
Transmission Electron ◽  
Scanning Electron

Lyophyllum palustre (Peck) Singer, a basidiomycete (Tricholomataceae) parasitizing Sphagnum, was examined for points of contact between hyphae and Sphagnum cells with the help of light microscopy, scanning electron microscopy, and transmission electron microscopy. Results indicate that the fungus attacks Sphagnum cells by penetrating cell walls and altering host cell protosplasm. In addition, the formation of additional partitioning cell walls in attacked living Sphagnum cells was observed.

Wilts caused by Verticillium species. A cytological survey of vascular alterations in leaves

1982 ◽  
Vol 60 (6) ◽  
pp. 825-837 ◽  
Author(s):  
Jane Robb ◽  
Alexandra Smith ◽  
Lloyd Busch
Keyword(s):  
Electron Microscopy ◽  
Cell Walls ◽  
Sem Analysis ◽  
Disease Symptoms ◽  
Vascular Tissues ◽  
Transmission Electron ◽  
Tem Method ◽  
Cytological Alterations ◽  
Host Parasite ◽  
Leaf Symptoms

Plants that are infected with fungi of the species Verticillium frequently develop foliar disease symptoms which may include one or more of the following: flaccidity, drying, chlorosis leading to necrosis, vascular browning, epinasty, and leaf abscission. A number of ultrastructural and chemical alterations occur in the vascular tissues of such leaves: deposition of brown pigments, coating of xylem vessel walls with abnormal material (i.e., lipid-rich coatings or fibrillar coatings), plugging of xylem vessels with gums, gels or tyloses, degeneration of parenchyma cells, and accumulation of abnormal electron dense materials in primary and secondary cell walls. Different host–parasite combinations exhibit different leaf symptoms and different cytological alterations. The purpose of the present survey was to determine whether the extent of any of the possible vascular alterations in leaves could be correlated with the wilting tendency of the host.Chrysanthemums, snapdragons, eggplants, sunflowers, potatoes, sycamore maples and hedge maples were infected with V. dahliae; alfalfa and hops were infected with V. albo-atrum. When leaf symptoms were well advanced, samples were taken from the major lateral leaf veins and were prepared for light (LM) and transmission electron microscopy (TEM) or scanning electron microscopy (SEM). The various types of alterations in the vascular tissues were identified by a correlated LM–TEM method and (or) SEM analysis and for each sample vein the proportion of vessels affected by each type of alteration was calculated. Four leaf samples, each from different plants, were analysed for each host. The visual symptoms, including vascular browning, were estimated subjectively. The degree of leaf flaccidity was correlated positively with the proportion of lipid-coated vessels and inversely with the degree of vascular browning. No other correlations were observed.

Nectary ultrastructure and secretory modes in three species of Tillandsia (Bromeliaceae) that have different pollinators

Botany ◽  
2013 ◽  
Vol 91 (11) ◽  
pp. 786-798 ◽  
Author(s):  
Stefano Mosti ◽  
Cynthia Ross Friedman ◽  
Ettore Pacini ◽  
Luigi Brighigna ◽  
Alessio Papini
Keyword(s):  
Electron Microscopy ◽  
Amino Acids ◽  
Lipid Droplets ◽  
Protein Crystals ◽  
Transmission Electron ◽  
Floral Nectaries ◽  
Secretion Product ◽  
Pollination Mode ◽  
Cell Wall Ingrowths ◽  
Holocrine Secretion

The floral nectaries of three Tillandsia L. spp. having different pollinators were investigated with transmission electron microscopy (TEM) to describe the previously unstudied ultrastructure of the nectar-producing tissues (primarily the epidermis) and also to determine if any differences in the ultrastructural features could be correlated to pollination mode. We determined that there were variations in nectaries among the three species, and that these may be linked to pollinator choice. Tillandsia seleriana Mez, which has a strict relationship with ants, had a nectary epithelium characterized by abundant dictyosomes and endoplasmic reticulum (ER), and a final degeneration stage possibly leading to holocrine secretion. The presence of protein crystals in epithelial plastids was correlated to a nectar enriched with amino acids and proteins, likely functioning to provide a protein-enriched diet and possibly defence against pathogens. Epithelial cells of the hummingbird-pollinated Tillandsia juncea (Ruiz et Pav.) Poir. nectary displayed cell wall ingrowths and dictyosomes and also contained cytoplasmic lipid droplets and protein crystals within plastids, both of which would enrich the nectar for hummingbirds. The nectary epithelium and the parenchyma of bat-pollinated Tillandsia grandis Schltdl. possessed a few cubic protein crystals in the plastids and its secretion product appeared electron transparent.

Immunolocalization of a proteinase of the sap-staining fungus Ophiostoma piceae using antibodies to proteinase K

1995 ◽  
Vol 73 (10) ◽  
pp. 1604-1610 ◽  
Author(s):  
C. Hoffert ◽  
S. Gharibian ◽  
C. Breuil ◽  
D. L. Brown
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Cell Walls ◽  
Polyclonal Antibodies ◽  
Immunogold Labelling ◽  
Proteinase K ◽  
Igg Antibodies ◽  
Extracellular Proteinase ◽  
Ophiostoma Piceae ◽  
Transmission Electron

Polyclonal antibodies were raised against proteinase K and were used to immunolocalize the major extracellular proteinase of the sap-staining fungus Ophiostoma piceae (Münch) H. and P. Sydow. Immunodot blotting showed that the IgG antibodies recognized both enzymes but reacted more strongly with proteinase K than with the O. piceae proteinase. Immunogold labelling and transmission electron microscopy revealed that the O. piceae proteinase was localized in the cell walls of O. piceae grown either in liquid media or wood. Key words: Ophiostoma piceae, proteinase, immunogold labelling, transmission electron microscopy, antibody, proteinase K.

Ultrastructure of hyperparasitism of Coniothyrium minitans on sclerotia of Sclerotinia sclerotiorum

1987 ◽  
Vol 65 (12) ◽  
pp. 2483-2489 ◽  
Author(s):  
H. C. Huang ◽  
E. G. Kokko
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Cell Wall ◽  
Sclerotinia Sclerotiorum ◽  
Cell Walls ◽  
Chemical Activity ◽  
Coniothyrium Minitans ◽  
Medullary Tissue ◽  
Transmission Electron

Transmission electron microscopy revealed that hyphae of the hyperparasite Coniothyrium minitans invade sclerotia of Sclerotinia sclerotiorum, resulting in the destruction and disintegration of the sclerotium tissues. The dark-pigmented rind tissue is more resistant to invasion by the hyperparasite than the unpigmented cortical and medullary tissues. Evidence from cell wall etching at the penetration site suggests that chemical activity is required for hyphae of C. minitans to penetrate the thick, melanized rind walls. The medullary tissue infected by C. minitans shows signs of plasmolysis, aggregation, and vacuolization of cytoplasm and dissolution of the cell walls. While most of the hyphal cells of C. minitans in the infected sclerotium tissue are normal, some younger hyphal cells in the rind tissue were lysed and devoid of normal contents.

Sign in / Sign up

Export Citation Format

Share Document