Etudes du cours des hyphes de Fomes fomentarius dans le bois d'Aesculus hippocastanum au microscope électronique à balayage

In a scanning electron microscope (SEM) study, the passage of penetrating hyphae of Fomes fomentarius (L.ex Fr.)Kickx was observed in a representative specimen of Aesculus hippocastanum L. The fungus hyphae appear in all cells of the wood and break through in numerous areas of the cell walls. It was noted that many pits serving as passageways were found; however, the cell wall was observed to be penetrated in many areas devoid of such pits. Apically secreted enzymes probably played a primary role in the process. The primary bore passages are widened by means of lateral enzyme secretion. The depth and sharpness of the SEM photographs are remarkable in that they allow one to follow the passage of the hyphae quite well.

Download Full-text

Euastrum (Zygnematophyceae) from Europea: diversity, ecology, distribution

Issues of modern algology (Вопросы современной альгологии) ◽

10.33624/2311-0147-2021-1(25)-85-92 ◽

2021 ◽

pp. 85-92

Author(s):

Olga V. Anissimova

Keyword(s):

Cell Wall ◽

Electron Microscope ◽

Scanning Electron Microscope ◽

European Part ◽

Water Bodies ◽

European Part Of Russia ◽

Scanning Electron

Euastrum is one of the most important genus of desmids, have been selected as widely represented in the flora of the water bodies of Europe. The algal samples were collected from different localities of ten regions of European part of Russia. Cells of 50 species of Euastrum was examined in scanning electron microscope. Cell wall of the Euastrum have some specific pits, which are called scrobicles. Its size, shape and quantity vary from species to species. Out of more than 250 species Euastrum, described 73 taxa for which the preference for acidity of the environment, biotopic confinement, and distribution over Europe and other continents are known. The dictionary of the most used terms is given.

Download Full-text

Neogene occurrences of the marine acritarch genusNannobarbophoraHabib and Knapp, 1982 emend., and the new speciesN. Gedlii

Journal of Paleontology ◽

10.1017/s0022336000043717 ◽

2003 ◽

Vol 77 (2) ◽

pp. 382-385 ◽

Cited By ~ 4

Author(s):

Martin J. Head

Keyword(s):

Electron Microscope ◽

Scanning Electron Microscope ◽

North Atlantic ◽

Diagnostic Feature ◽

Sem Study ◽

Scanning Electron

The stratigraphic utility of small marine acritarchs in the Neogene has been known for more than a decade (e.g., de Vernal and Mudie, 1989). Their potential for biostratigraphy in the Cretaceous is also well known, and was elegantly elucidated by Habib and Knapp (1982) in a detailed scanning electron microscope (SEM) study from the western North Atlantic. Habib and Knapp erected 12 new acritarch genera including the acanthomorph genusNannobarbophoraand its three speciesN. barbata(the name of the type),N. pistilla, andN. platforma. A diagnostic feature ofNannobarbophorais the presence of spinules concentrated on, or restricted to, the surface of distally closed processes. Excystment is by a simple linear split (Habib and Knapp, 1982, p. 347).

Download Full-text

Scanning Electron Microscopic Study of the Eggs of the Warthog Louse (Haematopinus Phacochoeri)

Microscopy and Microanalysis ◽

10.1017/s1431927600007455 ◽

1997 ◽

Vol 3 (S2) ◽

pp. 113-114

Author(s):

C. Baker ◽

E.D. Green

Keyword(s):

Electron Microscope ◽

Scanning Electron Microscope ◽

Environmental Changes ◽

General Structure ◽

Electron Microscopic ◽

Razor Blade ◽

Scanning Electron Microscopic Study ◽

Sem Study ◽

Scanning Electron Microscopic ◽

Scanning Electron

The large eggs of Haematopinus phacochoeri are found attached to the long dorsal mane bristles of the diurnal warthog. The eggs are generally exposed to great environmental stresses such as excessive sunlight and temperature as well as the occasional plunge under water or mud during grooming. This investigation was therefore undertaken to determine how the eggs of H. phococoeri are adapted to tolerate the various environmental changes it is constantly exposed to. To our knowledge no other SEM study on the eggs of this species has been performed.Specimens still attached to the bristles were fixed in 70% ethanol, dehydrated and ultrasonically cleaned. Some eggs were longitudinally sectioned with a razor blade to expose the chorionic layers. The eggs were critical point dried in liquid CO2, mounted and viewed by means of a Leica Stereoscan 420 scanning electron microscope.The general structure of the shell consists of two layers of chorion, i.e. the endo-and exochorion. These two layers are attached at the pre-formed line of weakness at the operculum and again near the hydropyle. Elsewhere these two layers are completely separated by the respiratory layer.

Download Full-text

Osmium Staining Fails to Detect Early Cell Wall Damage in Brown Rot Wood Decay

IAWA Journal ◽

10.1163/22941932-90001352 ◽

1994 ◽

Vol 15 (2) ◽

pp. 133-136

Author(s):

W. Wayne Wilcox

Keyword(s):

Cell Wall ◽

Electron Microscope ◽

Cell Walls ◽

Osmium Tetroxide ◽

Wood Decay ◽

Brown Rot ◽

X Ray ◽

Polarised Light ◽

Early Manifestation ◽

Scanning Electron

Loss of cell wall birefringence under polarised light in the light microscope is an important diagnostic characteristic for early stages of brown rot wood decay not available with the scanning electron microscope (SEM). Osmium tetroxide staining was explored as a means of visualising this early manifestation of decay in the SEM, but proved unsuccessful as X-ray spectroscopy indicated that osmium was evenly distributed across both distorted and non-distorted cell walls.

Download Full-text

Studies in the southern African species of Justicia and Siphonoglossa (Acanthaceae): indumentum

Bothalia ◽

10.4102/abc.v20i1.894 ◽

1990 ◽

Vol 20 (1) ◽

pp. 61-66 ◽

Cited By ~ 1

Author(s):

K. Immelman

Keyword(s):

Electron Microscope ◽

Scanning Electron Microscope ◽

Southern Africa ◽

Cell Walls ◽

African Region ◽

African Species ◽

Flora Of Southern Africa ◽

Southern African Region ◽

Trichome Types ◽

Scanning Electron

The trichome types present on all species of Justicia and Siphonoglossa in the southern African region (as defined by the Flora of southern Africa) were examined with the dissecting and with the Scanning Electron Microscope. Both glandular and eglandular trichomes were observed, the former comprising both sessile, peltate glands and stalked glands of various lengths. Eglandular trichomes are either straight or sharply bent (anvil-shaped), and comprise two to many cells. They are either smooth or have raised ornamentation on the cell walls. The presence and morphology of the trichomes on various organs is recorded and measured, and the range of trichomes seen was illustrated. The possible significance of trichome type and ornamentation in the taxonomy and ecology of the genera is discussed.

Download Full-text

Ultrastructure of conidiogenesis and appendage ontogeny in the coelomycete Bartalinia robillardoides

Canadian Journal of Botany ◽

10.1139/b03-100 ◽

2003 ◽

Vol 81 (11) ◽

pp. 1083-1090 ◽

Cited By ~ 6

Author(s):

M KM Wong ◽

E BG Jones ◽

M A Abdel-Wahab ◽

D WT Au ◽

L LP Vrijmoed

Keyword(s):

Cell Wall ◽

Electron Microscope ◽

Cell Walls ◽

Apical Cell ◽

Conidiogenous Cell ◽

Dense Layer ◽

Basal Cells ◽

Outer Electron ◽

Transmission Electron ◽

Scanning Electron

Conidiogenesis and conidial appendage ontogeny of the coelomycete Bartalinia robillardoides Tassi was studied at the light microscope, scanning electron microscope, and transmission electron microscope levels. Conidiogenesis in B. robillardoides is holoblastic. Appendage ontogeny begins as a cellular outgrowth of the apical and the basal cells of the young conidium, the former developing prior to the basal appendage. Conidia detach from the conidiogenous cells schizolytically. Mature conidial cell walls comprise two layers: an outer electron-dense layer, 3038 nm, and an inner less electron-dense layer, 100125 nm. The apical appendages arise from an outgrowth of the apical cell, which then branches to form the appendages. The single basal appendage arises from the junction between the basal cell of the conidium and the conidiogenous cell prior to conidial detachment from the conidiogenous cell, as an outgrowth of the conidial cell wall. Conidial appendage ontogeny is compared with those of other coelomycetes.Key words: Annellidic, appendage ontogeny, coelomycetes, holoblastic.

Download Full-text

Early Cretaceous striate tricolpate pollen from the Borehole Mersa Matruh 1, North West Desert, Egypt

Journal of Micropalaeontology ◽

10.1144/jm.7.2.201 ◽

1988 ◽

Vol 7 (2) ◽

pp. 201-215 ◽

Cited By ~ 23

Author(s):

James H. J. Penny

Keyword(s):

Electron Microscope ◽

Scanning Electron Microscope ◽

New Taxa ◽

Early Cretaceous ◽

North West ◽

Sem Study ◽

Stratigraphic Ranges ◽

Scanning Electron

Abstract. Striate tricolpate pollen has been recovered from Early Cretaceous samples of the borehole Mersa Matruh 1 in the N.W. Desert of Egypt. Scanning Electron Microscope (SEM) study has revealed fine details of their exine scupture, on the basis of which four new taxa, STRIOTRI-OVAL, STRIOTRI-SMOOTHMUR, STRIOTRI-SEGMUR and STRIORET-SMOOTH, are distinguished. The stratigraphic ranges of these are discussed and they are compared with other published species. They are among the oldest striate tricolpate pollen yet described, appearing in sediments of Early Aptian age, slightly predating the first reliable records of reticulate tricolpates in the sequence studied. The lack of earlier reticulate grains is attributed to possible sample failure. There is evidence that the true first appearance of tricoplate pollen in Egypt may be late Barrenian.

Download Full-text

Nonenzymatic Release of Intact Protoplasts from Mature Pollen of Bean

Journal of the American Society for Horticultural Science ◽

10.21273/jashs.115.4.640 ◽

1990 ◽

Vol 115 (4) ◽

pp. 640-643 ◽

Cited By ~ 3

Author(s):

M.L. Weaver ◽

V. Breda ◽

W. Gaffield ◽

H. Timm

Keyword(s):

Cell Wall ◽

Electron Microscope ◽

Phaseolus Vulgaris ◽

Scanning Electron Microscope ◽

Salt Solutions ◽

Cell Wall Degrading Enzymes ◽

Time Exposure ◽

Rapid Release ◽

Short Time ◽

Scanning Electron

A nonenzymatic technique using dilute salt solutions effected rapid release of viable protoplasts from mature bean (Phaseolus vulgaris L.) pollen. Protoplasm release started within 30 sec and was completed within 5 min in solutions of 0.02 to 0.06 m NaCl, or KCl, pH 6 to 9. The degree of release could be altered by changing the concentrations and ratios of CaCl2 and H3BO3 and by adding sucrose to either solidified or aqueous salt media. The surface of nonenzymatically released protoplasts was partially digested by short-time exposure to a mixture of cell wall-degrading enzymes and then examined by scanning electron microscope.

Download Full-text