Electron microscopy of vesicular-arbuscular mycorrhizae of yellow poplar. II. Intracellular hyphae and vesicles

1975 ◽  
Vol 21 (11) ◽  
pp. 1768-1780 ◽  
Author(s):  
Darrell A. Kinden ◽  
Merton F. Brown
Keyword(s):  
Electron Microscopy ◽  
Lipid Droplets ◽  
Arbuscular Mycorrhizae ◽  
Wall Material ◽  
Yellow Poplar ◽  
Cortical Cells ◽  
Dense Bodies ◽  
Vesicular Arbuscular ◽  
Abundant Cytoplasm ◽  
Mycorrhizal Roots

Intracellular hyphae and vesicles in mycorrhizal roots of yellow poplar were examined by electron microscopy. An investing layer of host wall material and cytoplasm enclosed the endophyte within the cells. Young developing hyphae contained abundant cytoplasm and few vacuoles. As hyphae matured, they became highly vacuolated and accumulated carbohydrate (glycogen) and lipid reserves. Mature vesicles were engorged with lipid droplets, possessed a trilaminate wall, and were also enclosed by host wall material and cytoplasm. Compared with uninfected cells, infected cortical cells showed an increase in cytoplasmic volume, enlarged nuclei, and a reduction of starch reserves. Host nuclei were always proximal to the hyphae during hyphal development and deterioration. While other cytoplasmic components of infected and uninfected cells were comparable, large electron-dense bodies occurred in vacuoles of most cells containing hyphae. Deterioration of intracellular hyphae occurred throughout the samples examined. Septa separated functional and degenerating portions of the hyphae. Hyphal deterioration involved degeneration and ultimate disappearance of fungal cytoplasm as well as collapse of hyphal walls. Based on these observations, the authors hypothesize that deterioration of the endophyte may release significant quantities of mineral nutrients, via hyphal contents, which are absorbed by the host.

Electron microscopy of vesicular-arbuscular mycorrhizae of yellow poplar. III. Host–endophyte interactions during arbuscular development

1975 ◽  
Vol 21 (12) ◽  
pp. 1930-1939 ◽  
Author(s):  
Darrell A. Kinden ◽  
Merton F. Brown
Keyword(s):  
Electron Microscopy ◽  
Arbuscular Mycorrhizae ◽  
Fungal Endophyte ◽  
Host Cells ◽  
Wall Material ◽  
Yellow Poplar ◽  
Transmission Electron ◽  
Abundant Cytoplasm ◽  
Mycorrhizal Roots ◽  
Infected Cells

Scanning- and transmission-electron microscopy were used to examine developing and mature functional arbuscules in mycorrhizal roots of yellow poplar. Arbuscules developed from intracellular hyphae which branched repeatedly upon penetration into the host cells. Intermediate and late stages of development were characterized by the production of numerous, short, bifurcate hyphae throughout the arbuscule. Mature arbuscules exhibited a coralloid morphology which resulted in a considerable increase in the surface area of the endophyte exposed within the host cells. Distinctive ultrastructural features of arbuscular hyphae included osmiophilic walls, nuclei, abundant cytoplasm, glycogen, and numerous small vacuoles. All arbuscular components were enclosed by host wall material and cytoplasm during development and at maturity. In infected cells, host nuclei were enlarged and the cytoplasm associated with the arbuscular branches typically contained abundant mitochondria, endoplasmic reticulum, and proplastids. Ultrastructural observations suggested that nutrient transfer may be predominantly directed toward the fungal endophyte during arbuscular development and while mature arbuscules remain functional.

Electron microscopy of vesicular-arbuscular mycorrhizae of yellow poplar. IV. Host–endophyte interactions during arbuscular deterioration

1976 ◽  
Vol 22 (1) ◽  
pp. 64-75 ◽  
Author(s):  
Darrell A. Kinden ◽  
Merton F. Brown
Keyword(s):  
Electron Microscopy ◽  
Arbuscular Mycorrhizae ◽  
Mineral Nutrients ◽  
Wall Material ◽  
Yellow Poplar ◽  
Cortical Cells ◽  
Morphological Alterations ◽  
Transmission Electron ◽  
Vesicular Arbuscular ◽  
Scanning Electron

Scanning electron stereoscopy and transmission electron microscopy were used to correlate morphological alterations and cytological phenomena associated with deterioration of arbuscules in yellow poplar mycorrhizae. Arbuscular degradation was initiated at the tips of the finest branches and progressed basipetally. Cytoplasm in arbuscular hyphae progressively deteriorated and was followed by collapse of the fungal walls. Degraded portions of the arbuscules aggregated into clumps comprised of host wall material and the distorted fungal walls. Host nuclei, abundant mitochondria, and proplastids were closely associated with arbuscular branches undergoing cytoplasmic deterioration and with clumped portions of the arbuscule which contained degraded hyphal branches. Most of the arbuscules observed had deteriorated to the clumped stage. Some cortical cells contained several clumped arbuscules and nearly mature, intact arbuscules which indicated that reinfection occurs even as degradative phenomena are in progress. It is suggested that substantial quantities of mineral nutrients may be made available to the host via degradation of fungal cytoplasm in the arbuscular hyphae preceding aggregation of degraded hyphae into discrete clumps.

Electron microscopy of vesicular-arbuscular mycorrhizae of yellow poplar. I. Characterization of endophytic structures by scanning electron stereoscopy

1975 ◽  
Vol 21 (7) ◽  
pp. 989-993 ◽  
Author(s):  
Darrell A. Kinden ◽  
Merton F. Brown
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Arbuscular Mycorrhizae ◽  
Yellow Poplar ◽  
Morphological Alterations ◽  
Vesicular Arbuscular Mycorrhizae ◽  
Host Cytoplasm ◽  
Vesicular Arbuscular ◽  
Scanning Electron

Vesicular-arbuscular mycorrhizae of yellow poplar (Liriodendron tulipifera L.) were examined by scanning electron microscopy. The morphology and spatial distribution of endophytic structures are illustrated. The use of stereoscopic techniques in conjunction with removal of host cytoplasm permits detection of subtle morphological alterations and progressive deterioration of the fungal component.

The morphology of vesicular – arbuscular mycorrhizae in Clintonia borealis and Medeola virginiana

1996 ◽  
Vol 74 (5) ◽  
pp. 679-685 ◽  
Author(s):  
Paul Widden
Keyword(s):  
Arbuscular Mycorrhizae ◽  
Deciduous Forest ◽  
Arbuscular Mycorrhizal ◽  
Cortical Layer ◽  
Cortical Cells ◽  
Vesicular Arbuscular Mycorrhizae ◽  
Forest Herbs ◽  
Vesicular Arbuscular ◽  
Innermost Layer ◽  
Inner Cortex

During a survey of the vesicular–arbuscular mycorrhizal (VAM) associations of forest herbs in a deciduous forest in the southern Laurentian mountains in Quebec, two liliaceous species, Clintonia borealis and Medeola virginiana, revealed very distinctive morphology. In both species, once the epidermis was penetrated, the fungus spread towards the centre of the root via intracellular hyphae until the innermost layer of the cortex was reached, at which point the fungus spread laterally and tangentially through the cortical cells adjacent to the endodermis via a series of banana-shaped projections (bobbits). These eventually differentiated into the arbuscules and the VAM might spread from this inner cortical layer back into the outer cortical layers. In C. borealis, the hyphae coiled in the cortex, and vesicles were formed in the upper cortical cells. In M. virginiana, no coiling took place, but extensive diverticulae were produced by the intracellular hyphae in the cortical cells, close to their point of exit, and vesicles were produced in the inner cortex as swellings from the bobbits. These two mycorrhizae have some similarities to one in Colchicum autumnale described by I. Gallaud (1905. Rev. Gen. Bot. 17). Keywords: vesicular–arbuscular mycorrhizae, Clintonia borealis, Medeola virginiana, Liliaceae, morphology.

Incidence and condition of vesicular–arbuscular mycorrhizae infections in the roots of sugar maple in relation to maple decline

1978 ◽  
Vol 8 (4) ◽  
pp. 375-379 ◽  
Author(s):  
Roberta A. Spitko ◽  
Terry A. Tattar ◽  
Richard A. Rohde
Keyword(s):  
Sugar Maple ◽  
Arbuscular Mycorrhizae ◽  
Mycorrhizal Infection ◽  
Fungal Symbiont ◽  
Crown Condition ◽  
Cortical Cells ◽  
Sugar Maples ◽  
Vesicular Arbuscular ◽  
University Of Massachusetts ◽  
The University

Twelve sugar maples (Acersaccharum Marsh.) on the campus of the University of Massachusetts were selected for the study in spring 1977. Trees chosen ranged from healthy to severely declined and were assigned to crown-condition classes of increasing severity from I to IV. Whole root samples from each tree were cleared in 10% KOH and stained in trypan blue to assess the degree of vesicular–arbuscular infection. Five sections of secondary feeder roots from each tree were selected at random and examined under a microscope. The number of infected cortical cells per centimetre of roots was counted to give an estimate of percent mycorrhizal infection for each tree. An inverse relationship was found between the degree of decline shown by the crown and the amount of mycorrhizal infection in the roots. Trees of class I had young infections showing extensive arbuscule development and few vesicles. In classes II to IV there was a decrease in the number of cortical cells infected by the fungus and an increase in vesicle formation, at times to the point where cortical cells were disrupted by their presence. In class IV, arbuscules that were present had undergone digestion of the fine branches so that only the collars were in evidence. Soil pH and nutritional status were determined but no relationship was found between these factors and the health of the fungal symbiont in the roots.

Soilless culture of vesicular–arbuscular mycorrhizae of cereals: effects of nutrient concentration and nitrogen source

1986 ◽  
Vol 64 (10) ◽  
pp. 2282-2294 ◽  
Author(s):  
J. P. Thompson
Keyword(s):  
Glomus Mosseae ◽  
Arbuscular Mycorrhizae ◽  
Rock Phosphate ◽  
Spore Production ◽  
Hydroponic Culture ◽  
Sand Culture ◽  
Soilless Culture ◽  
Nutrient Film Technique ◽  
Vesicular Arbuscular ◽  
Mycorrhizal Roots

The best productions of mycorrhizal roots from cereals in sand culture treated with four ratios of NO3 to NH4 in three concentrations of a balanced nutrient solution (Hewitt's) were (i) maize – Glomus mosseae: 30–50% colonization and 120–150 m of colonized root per plant from full-strength solution with 95–100% NO3-N; (ii) wheat – G. mosseae: 80–90% colonization from 0.1-strength solution and 40–50 m from 0.25-strength solution with 50–100% NO3-N; (iii) maize – Glomus fasciculatum: 70% and 120 m from 0.25-strength solution with 50% NO3-N; and (iv) wheat – G. fasciculatum: 25 – 30% and 10–15 m from 0.1-strength solution with 50 – 100% NH4-N. The highest nutrient strengths eliminated colonization in wheat or reduced numbers of vesicles and arbuscules. Vesicles were predominant at the lowest nutrient strengths. Ammonium reduced mycorrhizosphere pH, colonization, and sporocarp and ectocarpic spore production. Multiple regression showed best colonization with (i) maize – G. mosseae, pH > 7.4, and best vesicle and arbuscule development with root P < 0.1%; (ii) wheat – G. mosseae, pH 7.2–7.7, root P < 0.055%, and root N > 1.07%; (iii) maize – G. fasciculatum, pH 5.6–6.2, root P < 0.08%, and root N > 1.44%; and (iv) wheat – G. fasciculatum, pH 6.7–6.9. Maize – G. mosseae was grown by the nutrient film technique in 0.1-strength solution with NO3 and rock phosphate. Improving the production of the inoculum from hydroponic culture of cereals is discussed.

Colonization of crop and pasture species with vesicular–arbuscular mycorrhizal fungi and a negative correlation with root infection by Bipolaris sorokiniana

1989 ◽  
Vol 67 (3) ◽  
pp. 687-693 ◽  
Author(s):  
J. P. Thompson ◽  
G. B. Wildermuth
Keyword(s):  
Arbuscular Mycorrhizal Fungi ◽  
Mycorrhizal Fungi ◽  
Arbuscular Mycorrhizae ◽  
Arbuscular Mycorrhizal ◽  
Bipolaris Sorokiniana ◽  
Mycorrhizal Colonization ◽  
Root Infection ◽  
Vesicular Arbuscular Mycorrhizal Fungi ◽  
Vesicular Arbuscular ◽  
Mycorrhizal Roots

The roots of 37 crop and pasture species were assessed for vesicular–arbuscular mycorrhizae in a vertisol containing spores of vesicular–arbuscular mycorrhizal fungi mainly Glomus mosseae, and of the pathogenic fungus, Bipolaris sorokiniana. The level of mycorrhizal colonization of different hosts is an important aspect of managing crop sequences to reduce "long fallow disorder." All species except rapeseed in the Cruciferae and lupin in the Leguminosae were hosts, although perennial rye grass in the Gramineae had only very slight colonization. The percent root length colonized as assessed by the grid-intersect method ranged up to 60.5% for wheat in the winter series and up to 98.4% for mungbean in the summer series. Greatest weights of mycorrhizal roots were produced by phalaris grass, chickpea, safflower, cocksfoot, lucerne, and barley in the winter series and by lucerne, maize, canary seed, Sudan grass, grain sorghum, and buffel grass in the summer series. Although Gramineae as a group tends to have fine roots with a low percentage of mycorrhizal colonization, the total weight of mycorrhizal roots can be large, and they should be at least equal to legumes in effectiveness for breaking long fallow disorder. Percentages of mycorrhizal colonization determined by the grid-intersect and three slide methods were generally well correlated with one another, but all were less strongly correlated with weight of mycorrhizal roots for winter crops and were entirely uncorrelated with weight of mycorrhizal roots for summer crops. Significant inverse-regression relationships were obtained between infection of root segments (but not of stem bases) by B. sorokiniana and root colonization with vesicular–arbuscular mycorrhizae, indicating that vesicular–arbuscular mycorrhizal fungi antagonise root infection by B. sorokiniana.

Dynamics of arbuscule development and degeneration in onion, bean, and tomato with reference to vesicular–arbuscular mycorrhizae in grasses

1989 ◽  
Vol 67 (8) ◽  
pp. 2505-2513 ◽  
Author(s):  
Tom Alexander ◽  
Ronald Toth ◽  
Rose Meier ◽  
Hans Christian Weber
Keyword(s):  
Host Cell ◽  
Cell Volume ◽  
Arbuscular Mycorrhizae ◽  
Arbuscular Mycorrhizal Fungus ◽  
Mycorrhizal Fungus ◽  
Arbuscular Mycorrhizal ◽  
Electron Microscopic ◽  
Cortical Cells ◽  
Host Cytoplasm ◽  
Vesicular Arbuscular

A quantitative light and electron microscopic study of developing and degenerating arbuscules of the vesicular–arbuscular mycorrhizal fungus Glomus fasciculatum in onion, bean, and tomato was carried out to estimate three parameters during the colonization cycle and to compare these parameters with those in maize, oats, and wheat. The parameters are (i) Vv(a,c) the fraction of the host cell volume (c) occupied by the arbuscule (a); (ii) VV(cy,c) the fraction of the host cell volume occupied by host cytoplasm (cy); and (iii) SV(p,c) the ratio of the surface area of the host protoplast (p) to the volume of the whole host cell. Uninfected cortical cells contained 3.4% cytoplasm in onion, 3.1% in bean, and 3.5% in tomato. In cells with mature arbuscules, cytoplasm increased to 9.9% in onion, 14.2% in bean, and 13.6% in tomato. Cells with mature arbuscules contained 11.4% fungus in onion, 20.3% in bean, and 20.5% in tomato. The initial SV(p,c) in onion was 0.10 μm2/μm3 and in bean and tomato 0.11 μm2/μm3. This increased to 0.37 μm2/μm3 in onion, 0.82 μm2/μm3 in bean, and 0.54 μm2/μm3 in tomato by the time arbuscules were mature. Development of the arbuscule was estimated to take 2.5 days and occupied 33% of the total cycle time. The variation seen across host species can be used as an indicator of fungal and (or) host control for each parameter. Arbuscular parameters of onion were compared with those obtained by other authors.

Ultrastructural Cytopiasmic Changes of Adrenal Cortex During Pregnancy

1969 ◽  
Vol 27 ◽  
pp. 298-299
Author(s):  
T. M. Murad ◽  
Karen Israel ◽  
Jack C. Geer
Keyword(s):  
Adrenal Gland ◽  
Steroid Hormones ◽  
Adrenal Cortex ◽  
Lipid Droplets ◽  
Plasma Cholesterol ◽  
Adrenal Steroids ◽  
Dynamic Changes ◽  
Cortical Cells ◽  
Acetyl Coenzyme A ◽  
Adrenal Cortical Cells

Adrenal steroids are normally synthesized from acetyl coenzyme A via cholesterol. Cholesterol is also shown to enter the adrenal gland and to be localized in the lipid droplets of the adrenal cortical cells. Both pregnenolone and progesterone act as intermediates in the conversion of cholesterol into steroid hormones. During pregnancy an increased level of plasma cholesterol is known to be associated with an increase of the adrenal corticoid and progesterone. The present study is designed to demonstrate whether the adrenal cortical cells show any dynamic changes during pregnancy.

Copper Localization in Cirrhotic Rat Liver by Scanning Electron Microscopy

1969 ◽  
Vol 27 ◽  
pp. 38-39 ◽  
Author(s):  
J. C. Russ ◽  
E. McNatt
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Endoplasmic Reticulum ◽  
Electron Microscope ◽  
Copper Acetate ◽  
Lead Citrate ◽  
Dense Bodies ◽  
Transmission Electron ◽  
Electron Mode ◽  
Scanning Electron

In order to study the retention of copper in cirrhotic liver, rats were made cirrhotic by carbon tetrachloride inhalation twice weekly for three months and fed 0.2% copper acetate ad libidum in drinking water for one month. The liver tissue was fixed in osmium, sectioned approximately 2000 Å thick, and stained with lead citrate. The section was examined in a scanning electron microscope (JEOLCO JSM-2) in the transmission electron mode.Figure 1 shows a typical area that includes a red blood cell in a sinusoid, a disse, and a portion of the cytoplasm of a hepatocyte which contains several mitochondria, peribiliary dense bodies, glycogen granules, and endoplasmic reticulum.

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