scholarly journals Pseudohepatica duidensis, a new lichen from the venezuelan Amazonas

2000 ◽  
Vol 18 (1) ◽  
pp. 203-212 ◽  
Author(s):  
Vicente Marcano ◽  
Ernesto Palacios-Prü ◽  
Antonio Morales
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Thin Layer ◽  
Cell Walls ◽  
Secondary Compounds ◽  
Lower Surface ◽  
Chemical Constituent ◽  
Layer Chromatography ◽  
Scanning Electron ◽  
Gyrophoric Acid

The species Pseudohepatica duidensis Marcano, Palacios & Morales is described from the Venezuelan Amazonas. Special attention has been paid to the morphology and the chemistry (e.g. polysaccharides and secondary compounds), using scanning electron microscopy (SEM), thin-layer chromatography (TLC, HPTLC) and iodine reagent tests. Pseudohepatica duidensis is characterized by a very small (to 1 mm long), yellowish-green thallus, non-pored epicortex, yellowish lower surface with soredial protuberances, paraplectenchymatous upper cortex consisting of strongly sclerotic cells, cell walls with iodine reactions characteristic of lichenan and gyrophoric acid as relevant chemical constituent.

scholarly journals Anatomía de la semilla de Tigridia pavonia (Iridaceae)

2017 ◽  
pp. 66
Author(s):  
Aída Carrillo-Ocampo ◽  
E.M. Engleman
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Light Microscopy ◽  
Thin Layer ◽  
Cell Walls ◽  
Histochemical Staining ◽  
Stage Of Development ◽  
Scanning Electron

With methods of light microscopy, histochemical staining and scanning electron microscopy, it was found that the ovule in the seed of Tigridia pavonia (Iridaceae) is anatropous, bitegmic, and crassinucellate. During development, the exotegmen is crushed and the endotegmen persists with tannins in the lumens and in the walls, which also react positively for lignin. The exotesta contains tannins and its outer walls are convex, thickened, and cuticularized. The mesotesta has multiple layers, accumulates abundant lipids, and forms a bulge in the chalaza. The cell walls of the endotesta collapse and accumulate tannins. In the chalaza, a hypostasal cushion contains tannins in the lumens and in the walls, which also react positively for lignin. At the micropylar end of the seed there is an operculum which consists of: a) a slightly crushed exotegmen, b) an endotegmen with cuticular thickenings that are concentric with respect to the micropyle, c) hemispherical deposists of cutin on the anticlinal walls of the endotegmen, and c) a thin layer of endosperm that covers the radicle. During its cellular stage of development, the endosperm has conspicuous transfer walls at the chalazal end next to the nucella. The embryo is small and has a conical cotyledon.

The Lichen Genus Bulbothricella, A New Segregate in the Parmeliaceae from Venezuela

1996 ◽  
Vol 28 (5) ◽  
pp. 421-430 ◽  
Author(s):  
Vicente Marcano ◽  
Sari Mohali ◽  
Ernesto Palacios-Prü ◽  
Antonio Morales Méndez
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Thin Layer ◽  
Thin Layer Chromatography ◽  
New Genus ◽  
Single Species ◽  
Anatomical Structure ◽  
Chemical Characters ◽  
Layer Chromatography ◽  
Scanning Electron

AbstractThe new genus Bulbothricella (Lichenized Ascomycotina,Parmeliaceae with the single species B. amazonensis (Marcano, Galiz & Morales) Marcano, Galiz, Morales & Mohali is segregated from Bulbothrix. This conclusion is based on an investigation of morphological, anatomical and chemical characters using scanning electron microscopy and thin-layer chromatography. The new genus is characterized by a pored epicortex, 12—14 spores per ascus, obovate and acrogenous conidia, and an anatomical structure and cortical chemistry resembling that of Bulbothrix..

Actinomycetes in discolored wood of living silver maple

1981 ◽  
Vol 59 (1) ◽  
pp. 1-7 ◽  
Author(s):  
Robert A. Blanchette ◽  
John B. Sutherland ◽  
Don L. Crawford
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Carbon Source ◽  
Cell Walls ◽  
Hydroxybenzoic Acid ◽  
Liquid Media ◽  
Streptomyces Strain ◽  
Culture Techniques ◽  
Silver Maple ◽  
Scanning Electron

The greenish-brown margin of discolored wood in three living silver maple trees, Acer saccharinum L., was examined by scanning electron microscopy and microbiological culture techniques. Micrographs of xylem vessels revealed filamentous structures; some of them appeared to be actinomycetous hyphae. Actinomycetes identified as Streptomyces parvullus Waksman & Gregory, S. sparsogenes Owen, Dietz & Camiener, and a third Streptomyces strain were isolated repeatedly from discolored wood of each tree. These isolates grew in liquid media in the presence of 0.1% (w/v) concentrations of several phenols. Although other phenols included in the test were not substantially degraded, p-hydroxybenzoic acid was utilized as a carbon source by S. parvullus. All three actinomycetes inhibited growth of selected wood-inhabiting fungi when paired on malt agar. When inoculated on sterilized sapwood and discolored wood from silver maple, the actinomycetes colonized vessel walls and occlusions, but were not observed to decay cell walls.

Review — The Orientation of Cellulose Microfibrils in the cell walls of Tracheids in Conifers

IAWA Journal ◽  
2005 ◽  
Vol 26 (2) ◽  
pp. 161-174 ◽  
Author(s):  
Hisashi Abe ◽  
Ryo Funada
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Outer Layer ◽  
Cell Walls ◽  
Secondary Wall ◽  
Middle Layer ◽  
Cellulose Microfibrils ◽  
Conifer Species ◽  
Predominant Orientation ◽  
Scanning Electron

We examined the orientation of cellulose microfibrils (Mfs) in the cell walls of tracheids in some conifer species by field emission-scanning electron microscopy (FE-SEM) and developed a model on the basis of our observations. Mfs depositing on the primary walls in differentiating tracheids were not well-ordered. The predominant orientation of the Mfs changed from longitudinal to transverse, as the differentiation of tracheids proceeded. The first Mfs to be deposited in the outer layer of the secondary wall (S1 layer) were arranged as an S-helix. Then the orientation of Mfs changed gradually, with rotation in the clockwise direction as viewed from the lumen side of tracheids, from the outermost to the innermost S1 layer. Mfs in the middle layer of the secondary wall (S2 layer) were oriented in a steep Z-helix with a deviation of less than 15° within the layer. The orientation of Mfs in the inner layer of the secondary wall (S3 layer) changed, with rotation in a counterclockwise direction as viewed from the lumen side, from the outermost to the innermost S3 layer. The angle of orientation of Mfs that were deposited on the innermost S3 layer varied among tracheids from 40° in a Z-helix to 20° in an S-helix.

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.

High-Resolution Field Emission Scanning Electron Microscopy (FESEM) Imaging of Cellulose Microfibril Organization in Plant Primary Cell Walls

2017 ◽  
Vol 23 (5) ◽  
pp. 1048-1054 ◽  
Author(s):  
Yunzhen Zheng ◽  
Daniel J. Cosgrove ◽  
Gang Ning
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Cell Wall ◽  
High Resolution ◽  
Field Emission ◽  
Cell Walls ◽  
Cellulose Microfibrils ◽  
Critical Point Drying ◽  
Sputter Coating ◽  
Scanning Electron

AbstractWe have used field emission scanning electron microscopy (FESEM) to study the high-resolution organization of cellulose microfibrils in onion epidermal cell walls. We frequently found that conventional “rule of thumb” conditions for imaging of biological samples did not yield high-resolution images of cellulose organization and often resulted in artifacts or distortions of cell wall structure. Here we detail our method of one-step fixation and dehydration with 100% ethanol, followed by critical point drying, ultrathin iridium (Ir) sputter coating (3 s), and FESEM imaging at a moderate accelerating voltage (10 kV) with an In-lens detector. We compare results obtained with our improved protocol with images obtained with samples processed by conventional aldehyde fixation, graded dehydration, sputter coating with Au, Au/Pd, or carbon, and low-voltage FESEM imaging. The results demonstrated that our protocol is simpler, causes little artifact, and is more suitable for high-resolution imaging of cell wall cellulose microfibrils whereas such imaging is very challenging by conventional methods.

Parental Stress and Prechilling Effects on Pennsylvania Smartweed (Polygonum pensylvanicum) Achenes

Weed Science ◽  
1982 ◽  
Vol 30 (3) ◽  
pp. 243-248 ◽  
Author(s):  
James L. Jordan ◽  
David W. Staniforth ◽  
Catalina M. Jordan
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Zea Mays ◽  
Parental Stress ◽  
Cell Walls ◽  
Lipid Bodies ◽  
Transmission Electron ◽  
Polygonum Pensylvanicum ◽  
Scanning Electron

Pennsylvania smartweed (Polygonum pensylvanicum L.) achenes were harvested from plants growing either free from competition or in competition with corn (Zea mays L. ‘Pioneer 3780′) plants. Seeds were dormant when harvested. After 15 weeks of prechilling, 4 and 35% of the seeds germinated from plants with and without corn competition, respectively; after 30 weeks of prechilling, more than 92% of all seeds germinated. Scanning electron microscopy revealed that the carpel walls of achenes from plants with corn competition were porous with many channels. Carpel walls of achenes from plants without corn competition were without pores and channels. Transmission electron microscopy showed more lipid bodies in the embryo epidermal cells of seeds from plants with corn competition. Cell walls of embryos from non-prechilled seeds from plants with corn competition contained lipoidosomes that traversed cell walls. Lipoidosomes did not occur in cells of prechilled seeds.

Ultrastructure and influences of temperature on the in vitro production of Coprinus psychromorbidus sclerotia

1987 ◽  
Vol 65 (1) ◽  
pp. 124-130 ◽  
Author(s):  
James A. Traquair ◽  
Denis A. Gaudet ◽  
Eric G. Kokko
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Cell Walls ◽  
Colony Growth ◽  
In Vitro Production ◽  
Intercellular Matrix ◽  
Sclerotium Production ◽  
First Time ◽  
Scanning Electron

The effects of temperature on the production of sclerotia by the snow mold basidiomycete, Coprinus psychromorbidus, are described for the first time. Numbers of sclerotia produced and the optimum temperature for sclerotium production were variable for isolates observed. In general, the influence of temperature on sclerotium production was independent of its influence on colony growth. Optimal temperatures for production of sclerotia were higher than those for radial growth of colonies. Scanning electron microscopy revealed a centripetal pattern of differentiation in developing sclerotia. Distinctive rind, cortex, and medulla were evident after 8 to 10 weeks. Rind and cortex were multilayered. Thick-walled cells were cemented together by an amorphous intercellular matrix. Melanin was located in the rind cell walls for the first time by scanning electron microscopy and backscattered electron imaging of silver-stained sections. With the transmission electron microscope, melanin granules were observed only in the intercellular matrix and outer layers of rind cell walls. Inflated medullary cells were predominantly thin walled and contained vacuolate cytoplasm.

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