Ontogeny of Alnus rubra – Alpova diplophloeus ectomycorrhizae. II. Transmission electron microscopy

1989 ◽  
Vol 67 (1) ◽  
pp. 201-210 ◽  
Author(s):  
H. B. Massicotte ◽  
C. A. Ackerley ◽  
R. L. Peterson
Keyword(s):  
Electron Microscopy ◽  
Epidermal Cells ◽  
Root Cap ◽  
Alnus Rubra ◽  
Golgi Bodies ◽  
Hartig Net ◽  
Transmission Electron ◽  
Meristem Zone ◽  
Basal Portion ◽  
Branching System

Ultrastructural features of the two symbionts in ectomycorrhizae formed between Alnus rubra and Alpova diplophloeus change with developmental stage. In the root cap – meristem zone, hyphae penetrate between vacuolated root cap cells and become appressed to epidermal cells containing small vacuoles, plastids with starch, numerous Golgi bodies, mitochondria, and endoplasmic reticulum cisternae. In the young Hartig net zone, hyphae with few vacuoles penetrate between vacuolated epidermal cells that still contain numerous Golgi bodies but now have plastids with small starch grains. Hartig net hyphae begin to branch and eventually form a complex branching system in the mature Hartig net zone. Hartig net hyphae in the basal portion of the ectomycorrhizae synthesize lipid and finally become vacuolated.

Ontogeny of Eucalyptus pilularis – Pisolithus tinctorius ectomycorrhizae. II. Transmission electron microscopy

1987 ◽  
Vol 65 (9) ◽  
pp. 1940-1947 ◽  
Author(s):  
H. B. Massicotte ◽  
R. L. Peterson ◽  
C. A. Ackerley ◽  
A. E. Ashford
Keyword(s):  
Cortical Layer ◽  
Epidermal Cells ◽  
Root Cap ◽  
Pisolithus Tinctorius ◽  
Dense Layer ◽  
Hartig Net ◽  
Transmission Electron ◽  
Fungal Hyphae ◽  
Cytoplasmic Content ◽  
Eucalyptus Pilularis

Eucalyptus pilularis – Pisolithus tinctorius ectomycorrhizae were synthesized in growth pouches, and ultrastructural features of the two symbionts were documented during ontogeny. In the root cap – meristem zone, fungal hyphae envelop the root cap and penetrate between root cap cells. These fungal hyphae have numerous organelles and nuclei, some of which are in mitosis. The inner mantle hyphae in this zone and in the pre-Hartig net zone are heterogeneous in cytoplasmic content and are separated from the epidermis by an electron-dense layer. In the young Hartig net zone, hyphae penetrate between epidermal cells which contain electron-dense vacuolar deposits. In this zone and in the older Hartig net zone, hyphae do not penetrate beyond the epidermis and therefore a paraepidermal Hartig net is formed. The outer cortical layer develops as a hypodermis with suberized cell walls. The root–fungus interface consists of Hartig net hyphae which form a labyrinthine wall system and epidermal cells which are enlarged radially and contain electron-dense vacuolar deposits.

Structure and ontogeny of Alnus crispa – Alpova diplophloeus ectomycorrhizae

1986 ◽  
Vol 64 (1) ◽  
pp. 177-192 ◽  
Author(s):  
H. B. Massicotte ◽  
R. L. Peterson ◽  
C. A. Ackerley ◽  
Y. Piché
Keyword(s):  
Structural Changes ◽  
Hyphal Growth ◽  
Root Surface ◽  
Epidermal Cells ◽  
Transfer Cells ◽  
Wall Ingrowths ◽  
Alnus Crispa ◽  
Hartig Net ◽  
Fungal Hyphae ◽  
Branching System

Alnus crispa (Ait.) Pursh seedlings were grown in plastic pouches and inoculated with Frankia to induce nodules and subsequently with Alpova diplophloeus (Zeller & Dodge) Trappe & Smith to form ectomycorrhizae. The earliest events in ectomycorrhiza formation involved contact of the root surface by hyphae, hyphal proliferation to form a thin mantle, and further hyphal growth to form a thick mantle. Structural changes in the host, the mycosymbiont, and the fungus–epidermis interface were described at various stages in the ontogeny of ectomycorrhizae. Fungal hyphae in contact with epidermal cells in the regions of intercellular penetration and paraepidermal Hartig net developed numerous rough endoplastic reticulum cisternae. In more proximal regions of the mycorrhiza, these gradually became fewer in number and smooth. A complicated labyrinthine wall branching system also developed in the fungus in these regions. Concurrently, epidermal cells formed wall ingrowths in regions adjacent to Hartig net hyphae. There was a gradient in the formation of these epidermal transfer cells as the mycorrhiza developed, and an additional deposition of secondary cell wall over the wall ingrowths occurred as transfer cells senesced. Nonmycorrhizal control roots did not develop epidermal wall ingrowths. Electron-dense material, which was also autofluorescent, was deposited in the outer tangential walls of the exodermis contiguous to the paraepidermal Hartig net.

Callose-containing deposits in relation to root-hair infections of Alnus rubra by Frankia

1990 ◽  
Vol 68 (4) ◽  
pp. 798-802 ◽  
Author(s):  
A. M. Berry ◽  
M. E. McCully
Keyword(s):  
Electron Microscopy ◽  
Hair Cells ◽  
Root Hair ◽  
Vascular Tissue ◽  
Root Hairs ◽  
Alnus Rubra ◽  
Blue Fluorescence ◽  
Electron Dense Material ◽  
Transmission Electron ◽  
Infected Root

Light microscopy, aniline-blue fluorescence histochemistry, and transmission electron microscopy were used to elucidate the nature of localized wall deposition in infected and uninfected root hairs on nodulated roots of Alnus rubra Bong, inoculated with the nitrogen-fixing symbiont, Frankia HFPAr13. Callose-containing papillae were found only in epidermal hair cells and not in cortical or vascular tissue. At the site of successful root-hair wall penetration, transfer cell-like wall ingrowths were elaborated, but callose was not detected. At sites of arrested root-hair infections, complex deposits consisting of callose, fibrillar components, and electron-dense material surrounded the incipient hyphal infection. The cytoplasm of root hairs containing arrested infections was deteriorated compared with successfully infected root hairs.

Papilla response of barley epidermal cells caused by Erysiphe graminis: rate and method of deposition determined by microcinematography and transmission electron microscopy

1979 ◽  
Vol 57 (8) ◽  
pp. 898-913 ◽  
Author(s):  
Richard J. Zeyen ◽  
W. R. Bushnel
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Amorphous Material ◽  
Time Lapse ◽  
Epidermal Cells ◽  
Erysiphe Graminis ◽  
Sequence Of Events ◽  
Transmission Electron ◽  
Wall Appositions ◽  
Entire Sequence

Papillae were deposited in barley epidermal cells directly beneath appressoria of Erysiphe graminis f. sp. hordei and appeared as hemispherical, internal wall appositions. The papilla response began shortly after the formation of a rapidly moving cytoplasmic aggregate beneath the appressorium. As documented in coleoptile tissue by time-lapse light microcinematography, the papillae grew rapidly for 20–30 min after becoming visible, their radii increasing by 0.1 μm/min. For small papillae, deposition continued for about 30 min; for larger papillae, deposition continued for 120–180 min. Results with transmission electron microscopy on leaf epidermal cells suggested that papilla deposition by host cytoplasmic aggregates can be divided into four sequential stages: (i) the deposition of osmiophilic (lipidic) materials, (ii) the deposition and partial compaction of nonosmiophilic, amorphous material (probably insoluble polysaccharides), (iii) compaction of nonosmiophilic, amorphous material, and (iv) the incorporation of osmiophilic material into the host wall and into the compacted nonosmiophilic, amorphous material. At maturity, the papillae are hardened, electron-opaque wall appositions that may be effective in preventing fungal penetration and development. Failure of papillae to prevent fungal penetration and development may be related to the inability of the epidermal cells to complete the entire sequence of events in papilla deposition before attempted fungal penetration.

Brittle fracture of epidermal cells by liquid shear

1976 ◽  
Vol 20 (3) ◽  
pp. 699-705
Author(s):  
G.M. Gray ◽  
H.J. Yardley
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Phase Contrast ◽  
Epidermal Cells ◽  
Transmission Electron ◽  
The Press ◽  
Contrast Microscopy ◽  
Cell Fragments ◽  
Scanning Electron ◽  
Liquid Shear

A suspension of epidermal cells obtained from pig tail skin by trypsinization was subjected to high liquid-shear forces in a French press. The material issuing from the press was examined by phase-contrast microscopy, transmission electron microscopy and scanning electron microscopy. The cytoskeleton of tonofibrils retained the shape of cell fragments, and subcellular organelles remained enmeshed in the network of tonofibrils. Examination of some cell fragments by scanning electron microscopy revealed the internal organization of the tonofibrils. The relevance of these findings to the problem of isolating subcellular fractions from epidermis is discussed.

Ultrastructure des ectomycorhizes synthétiques à Hebeloma alpinum et Hebeloma marginatulum de Dryas octopetala

1981 ◽  
Vol 59 (11) ◽  
pp. 2160-2166 ◽  
Author(s):  
J. C. Debaud ◽  
R. Pepin ◽  
G. Bruchet
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Cortical Cells ◽  
Hyphal Morphogenesis ◽  
Hartig Net ◽  
Transmission Electron ◽  
Dryas Octopetala ◽  
Alpine Species ◽  
Means Of Transmission

Ectomycorrhizas of Dryas octopetala (Rosaceae) were synthesized with two alpine species of Hebeloma and observed by means of transmission electron microscopy. The mycorrhizas studied here were harvested at the time of fruiting of the associated fungi. The ultrastructure of the mycelial sheath, Hartig net, host cortical cells, and host–mycobiont interface was thus defined from very active, functional, living structures. Following analysis of the results, an interpretation of hyphal morphogenesis in the sheath and in the Hartig net is proposed.

scholarly journals The larval midgut of Anticarsia gemmatalis (Hübner) (Lepidoptera: Noctuidae): light and electron microscopy studies of the epithelial cells

2004 ◽  
Vol 64 (3b) ◽  
pp. 633-638 ◽  
Author(s):  
S. M. Levy ◽  
A. M. F. Falleiros ◽  
E. A. Gregório ◽  
N. R. Arrebola ◽  
L. A. Toledo
Keyword(s):  
Electron Microscopy ◽  
Endocrine Cells ◽  
Secretory Granules ◽  
Light And Electron Microscopy ◽  
Cell Types ◽  
Anticarsia Gemmatalis ◽  
Epithelial Tissue ◽  
Basal Region ◽  
Transmission Electron ◽  
Basal Portion

The morphology of the midgut epithelium cells of Anticarsia gemmatalis (Hübner) larvae is described by light and transmission electron microscopy. The midgut of A. gemmatalis is the largest portion of the digestive tract, with three distinct regions: proximal, media and distal. Its wall is formed by pseudostratified columnar epithelial tissue having four cell types: columnar, goblet, regenerative, and endocrine cells. The columnar cells are numerous and long, with the apical portion showing many lengthy microvilli and the basal portion invaginations forming a basal labyrinth. The goblet cells have a large goblet-shaped central cavity delimited by cytoplasmic projections filled with mitochondria. The regenerative cells present electron-dense cytoplasm and few organelles. The endocrine cells are characterized by electron-dense secretory granules, usually concentrated in the cytoplasm basal region.

Ultrastructural Changes in Root Cap Cells of Two Australian Native Grass Species Following Exposure to Aluminium

1997 ◽  
Vol 24 (2) ◽  
pp. 165 ◽  
Author(s):  
Simon A. Crawford ◽  
Sabine Wilkens
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Root Cap ◽  
Ultrastructural Changes ◽  
Grass Species ◽  
Aluminium Tolerance ◽  
Secretory Vesicles ◽  
Native Grass ◽  
Transmission Electron

Transmission electron microscopy was used to investigate ultrastructural changes in root cap cells of two aluminium-tolerant native grass species, Danthonia linkii Kunth and Microlaena stipoides (Labill.) R.Br., following exposure to Al. Quantitative differences in root cap cells and organelles in response to 0–10 ppm aluminium were determined using image analysis of electron micrographs. Changes to the size of root cap cells due to exposure to Al were similar in the two species with a low Al concentration (1–2 ppm) resulting in larger cells, while higher Al levels (5–10 ppm) reduced cell size. In peripheral cap cells of the more Al-tolerant M. stipoides, the size of secretory vesicles was not affected by exposure to Al, while in peripheral cap cells of the less Al-tolerant D. linkii, exposure to Al resulted in significantly smaller secretory vesicles being produced. Central root cap cells from control plants of M. stipoides contained 90% more dictyosomes and had 50% larger amyloplasts than D. linkii. Measurement of mucilage droplets showed that roots of M. stipoides produced much more mucilage than D. linkii. Exposure of roots of M. stipoides to Al in the range 2–10 ppm had no effect on the size of mucilage droplets produced. The possible role of mucilage production in aluminium tolerance is discussed.

Epidermal cells cultured on a collagen-based material

1986 ◽  
Vol 44 ◽  
pp. 212-213
Author(s):  
C. J. Doillon ◽  
A. J. Wasserman ◽  
R. A. Berg ◽  
F.H. Silver
Keyword(s):  
Electron Microscopy ◽  
Effective Means ◽  
Phenotypic Expression ◽  
Culture Conditions ◽  
Epidermal Cells ◽  
Wound Coverage ◽  
Transmission Electron ◽  
Cell Culture Conditions ◽  
Cells Cultured

Transmission electron microscopy is an effective means of characterizing the phenotypic expression of epidermal cells. Epidermal cells cultured on plastic dishes proliferate into several layers and differentiate in the same manner as in vivo. Epidermal cells may be cultured on a collagen-based material which can be used as a synthetic epidermis for wound coverage instead of a skin autograft. The purpose of this study is to characterize and compare the morphology of epidermal cells grown on plastic, collagen sheets, and collagen sponges under similar cell culture conditions.

A comparison of the death induced by fungal invasion or toxic chemicals in cowpea epidermal cells. II. Responses induced by Erysiphe cichoracearum

1988 ◽  
Vol 66 (4) ◽  
pp. 624-634 ◽  
Author(s):  
Susan L. F. Meyer ◽  
Michèle C. Heath
Keyword(s):  
Electron Microscopy ◽  
Cytoplasmic Streaming ◽  
Epidermal Cells ◽  
Toxic Chemicals ◽  
Ultrastructural Changes ◽  
Powdery Mildew Fungus ◽  
Fresh Tissue ◽  
Golgi Bodies ◽  
Erysiphe Cichoracearum ◽  
Cytoplasmic Aggregate

Cowpea leaves were inoculated with the plantain powdery mildew fungus, Erysiphe cichoracearum, and fresh epidermal cells overlying veins were examined by light microscopy before being cleared or prepared for electron microscopy. Fungal appressoria usually formed a haustorium in the underlying nonhost cell, but only after what appeared to be an unsuccessful penetration attempt that induced a transient cytoplasmic aggregate, a ring of autofluorescence in the plant wall (best seen in cleared tissue), and in two examples observed ultrastructurally, a small penetration peg embedded in a callose-like papilla. The haustorium developed from a different penetration peg and elicited the death of the invaded cell. As reported for the death of cowpea epidermal cells elicited by CuCl2, cytoplasmic changes that occurred rapidly in fresh tissue after cytoplasmic streaming had stopped correlated closely with changes in ultrastructure. Compared with the CuCl2 study, microtubules and Golgi bodies disappeared faster and membranes appeared more disorganized. These data suggest that in cowpea epidermal cells, ultrastructural changes accurately predict the onset of cell death and may also reflect differences in its modes of induction.

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