scholarly journals An Electron Microscopic Investigation of the Cell Wall Organization of Conifer Tracheids and Conifer Cambium

1950 ◽  
Vol 3 (3) ◽  
pp. 265 ◽  
Author(s):  
AJ Hodge ◽  
AB Wardrop
Keyword(s):  
Cell Wall ◽  
Microscopic Investigation ◽  
Electron Microscopic Investigation ◽  
Electron Micrograph ◽  
Electron Microscopic ◽  
X Ray ◽  
Inner Surface ◽  
Cell Wall Organization ◽  
Optical Evidence

An electron micrograph of a replica of the inner surface of the secondarycell wall of a conifer tracheid, demonstrating the almost transverse orientationof the microfibrils in this layer, is presented. This evidence provides confirmationof the type of cell wall organization of conifer tracheids proposed inother investigations on the basis of X-ray and optical evidence and of microscopicexamination. The existence of fibrils of 50-100 A in diameter has beendemonstrated in cell wall fragments obtained by the disintegration of cambiuminitials and of conifer tracheids. It is suggested that these microfibrilsmay correspond to the "micelles" or "crystalline regions" inferred from X-rayexamination.

Electron microscopy of barley root infection by the fungal pathogen Bipolaris sorokiniana

1991 ◽  
Vol 69 (12) ◽  
pp. 2724-2731 ◽  
Author(s):  
H. Carlson ◽  
U. Stenram ◽  
M. Gustafsson ◽  
H.-B. Jansson
Keyword(s):  
Cell Wall ◽  
Bipolaris Sorokiniana ◽  
Root Surface ◽  
Microscopic Investigation ◽  
Electron Microscopic Investigation ◽  
Barley Root ◽  
Outer Cortex ◽  
Electron Microscopic ◽  
Helminthosporium Sativum

An electron microscopic investigation of barley roots infected in vitro by Bipolaris sorokiniana showed the existence of an extracellular sheath on germ tubes and appressoria attached to the root surface. Growth of the fungus in the epidermis and outer cortex was predominantly intracellular, whereas in the inner cortex the hyphae observed were mainly intercellular. Hyphae could not be detected in the stele 24 or 72 h after inoculation. Enzymatic activity in the apex of penetration hyphae is a possible explanation of the electron-dense areas seen in host cell walls 72 h after inoculation. Separation of plasmalemma from cell wall and degeneration of host nuclei and mitochondria were other infection-induced changes commonly seen. A host response to fungal infection involved the development of papillae between the plasma membrane and cell wall of the plant as well as around fungal hyphae. Key words: Bipolaris sorokiniana, Cochliobolus sativus, Helminthosporium sativum, Hordeum vulgare, barley, root, microscopy.

The mechanism of surface growth involved in the differentiation of fibres and tracheids

1954 ◽  
Vol 2 (2) ◽  
pp. 165 ◽  
Author(s):  
AB Wardrop
Keyword(s):  
Cell Wall ◽  
Pinus Radiata ◽  
Microscopic Investigation ◽  
Electron Microscopic Investigation ◽  
Extension Growth ◽  
Potato Tubers ◽  
Electron Microscopic ◽  
Dimensional Changes ◽  
Storage Parenchyma ◽  
Xylem Elements

An electron microscopic investigation has been made of the differentiating xylem elements of Pinus radiata, Eucalyptus elaeophora, and Ulmus sp. In the tips of fibres and tracheids there is a tendency for the microfibrils of cellulose to be oriented in the direction of growth. It is considered that this orientation can be disturbed by subsequent dimensional changes in the cell. The thin areas of the differentiating cells which are involved in the so-called "mosaic growth" have been compared with the regions of the cell wall penetrated by plasmodesmata in the storage parenchyma of potato tubers. The suggestion is made that the thin areas are regions of the cell wall penetrated by plasmodesmata, or are developing primary pit fields. The implications of this concept, with respect to intercellular readjustment and to the differences between fibres and tracheids in extension growth, are discussed.

scholarly journals An Electron Microscopic Investigation into the Effect of EDTA on Plant Cell Wall

1960 ◽  
Vol 7 (2) ◽  
pp. 335-338 ◽  
Author(s):  
Shimon Klein ◽  
B. Ginzburg
Keyword(s):  
Cell Wall ◽  
Plant Cell Wall ◽  
Microscopic Investigation ◽  
Uranyl Acetate ◽  
Electron Microscopic Investigation ◽  
Wall Structure ◽  
Acetate Solution ◽  
Root Tips ◽  
Electron Microscopic ◽  
Thin Sections

To study the effect of EDTA on cell wall structure and the reversal of this effect by uranyl ion, thin sections of pea root tips were examined in the electron microscope. EDTA is known to facilitate separation of the cells in root tips. When sections of fixed and embedded EDTA-treated roots are floated on a uranyl-acetate solution, a loose network is revealed that would seem to be cellulose. Incorporation of uranyl into the roots, if it occurs prior to fixation, brings about recementation of the cells. After such treatment, a marginal darker area and a median brighter one can be observed in the wall, and the whole structure appears more compact again. Comparison of the results of the various treatments suggests that cellulose-cementing material is dispersed throughout the entire wall, and that its distribution parallels that of cellulose.

Light and electron microscopic investigation of adenohypophyses of germfree, food-restricted, and germfree-food restricted aging, male lobund-wistar rats

1988 ◽  
Vol 46 ◽  
pp. 352-353
Author(s):  
G. Ilse ◽  
K. Kovacs ◽  
N. Ryan ◽  
T. Sano ◽  
L. Stefaneanu ◽  
...  
Keyword(s):  
Wistar Rats ◽  
Microscopic Investigation ◽  
Electron Microscopic Investigation ◽  
Aging Male ◽  
Sprague Dawley ◽  
Electron Microscopic ◽  
Sprague Dawley Rats ◽  
Old Rats ◽  
Ad Libitum ◽  
Microscopic Findings

Germfree state and food restriction have been shown to increase life span and delay tumor occurrence in rats. We report here the histologic, immunocytochemical and electron microscopic findings of adenohypophyses of aging, male Lobund-Wistar rats raised at Lobund Laboratories. In our previous study, the morphologic changes in the adenohypophyses of old rats have been extensively investigated by histology, immunocytochemistry and electron microscopy. Lactotroph adenomas were frequent in Long-Evans and Sprague-Dawley rats, whereas gonadotroph adenomas were frequent in Sprague-Dawley and Wistar rats.Male Lobund-Wistar rats were divided into four groups: 1) conventional, which were raised under normal non-germfree environment and received food ad libitum; 2) germfree-food ad libitum; 3) conventional environment-food restricted and 4) germfree-food restricted. The adenohypophyses were removed from 6-month-, 18-month- and 30-month-old rats. For light microscopy, adenohypophyses were fixed in formalin and embedded in paraffin.

An Electron Microscopic Study of the Acute Effects of Hypothalamic Releasing Factors on the Anterior Pituitary Gland

1968 ◽  
Vol 26 ◽  
pp. 232-233
Author(s):  
P.W. Coates ◽  
E.A. Ashby ◽  
L. Krulich ◽  
A. Dhariwal ◽  
S. McCann
Keyword(s):  
Anterior Pituitary ◽  
Microscopic Investigation ◽  
Uranyl Acetate ◽  
Electron Microscopic Investigation ◽  
Electron Microscopic ◽  
Tissue Samples ◽  
Thin Sections ◽  
Dense Membrane ◽  
Membrane Bound ◽  
Releasing Factors

The morphologic effects on somatotrophs of crude sheep hypothalamic extract prepared from stalk-median eminence were studied by electron microscopy in conjunction with concurrently run bioassays performed on the same tissue samples taken from young adult male Sherman rats.Groups were divided into uninjected controls and injected experimentals sacrificed at 5', 15', and 30' after injection. Half of each anterior pituitary was prepared for electron microscopic investigation, the other half for bioassay. Fixation using collidine buffered osmium tetroxide was followed by dehydration and embedment in Maraglas. Uranyl acetate and lead citrate were used as stains. Thin sections were examined in a Philips EM 200.Somatotrophs from uninjected controls appeared as described in the literature (Fig. 1). In addition to other components, these cells contained moderate numbers of spherical, electron-dense, membrane-bound granules approximately 350 millicrons in diameter.

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