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.

Temporal change (1988–1990) in sugar maple health, and factors associated with crown condition

1992 ◽  
Vol 22 (11) ◽  
pp. 1776-1784 ◽  
Author(s):  
Douglas C. Allen ◽  
Charles J. Barnett ◽  
Imants Millers ◽  
Denis Lachance
Keyword(s):  
Sugar Maple ◽  
Temporal Change ◽  
Severe Drought ◽  
Root Damage ◽  
Crown Condition ◽  
Factors Associated ◽  
Crown Transparency ◽  
Sugar Maples ◽  
Foliage Density ◽  
Crown Dieback

Change in the health of sugar maple (Acersaccharum Marsh.) and associated northern hardwoods was evaluated for 3 years (1988–1990) in seven states and four provinces. Generally, levels of crown dieback and crown transparency (a measure of foliage density) in 165 stands decreased during this period. In 1990, less than 7% of all dominant–codominant sugar maples (n = 7317) exhibited crown dieback ≥ 20%. Significantly (p = 0.05) fewer of these maples were classified as having high crown transparency (≥ 30%) in 1990 compared with 1988. Crowns of maples that received moderate (31–60%) or heavy (> 60%) pear thrips (Taeniothripsinconsequens (Uzel)) damage for 1 year recovered the following year. Crowns of maples exposed to severe drought in 1988 (Wisconsin) continued to show the effects (high transparency) of this stress in 1990. A majority (69–71%) of the dominant–codominant sugar maples with high (≥ 20%) crown dieback had bole and (or) root damage. Of those maples with crown dieback ≥ 50%, 86% had bole and (or) root damage. The condition of sugar maple in operating sugar bushes and undisturbed stands was similar. The condition of sugar maple crowns was similar in locations presumably exposed to low, medium, and high levels of sulfate deposition.

Vesicular–arbuscular mycorrhizae in the Chenopodiaceae and Cruciferae: do they occur?

1978 ◽  
Vol 56 (22) ◽  
pp. 2813-2817 ◽  
Author(s):  
Marc C. Hirrel ◽  
H. Mehravaran ◽  
J. W. Gerdemann
Keyword(s):  
Arbuscular Mycorrhizae ◽  
Chenopodium Album ◽  
Mycorrhizal Infection ◽  
Va Mycorrhizae ◽  
Glomus Fasciculatus ◽  
Vesicular Arbuscular ◽  
Companion Plant ◽  
Resistance To Infection ◽  
Companion Plants ◽  
Test Plants

Members of the Chenopodiaceae and Cruciferae were reported to be nonmycorrhizal by early investigators; more recently, some species in these families have been reported to have low or in some cases high levels of vesicular–arbuscular (VA) mycorrhizal infection. In our experiments, a sparse vesicular (chlamydospore) infection by Glomus fasciculatus was found in four species of Chenopodiaceae and two species of Cruciferae but only when grown in the presence of a mycorrhizal companion plant, citrus or onion. No arbuscules were observed in infected roots. Chenopodium album had the highest incidence of infection (5%). Infection was restricted to older tissue and penetration of the vascular cylinder was common, which is atypical of VA mycorrhizae. As hyphae from mycorrhizal companion plants grew through the soil, they encountered older roots of the test plants which probably offered little or no resistance to infection. In documenting the occurrence of VA mycorrhizae in any species, it is important to observe whether the plant is growing by itself or if there are mycorrhizal plants closely associated with it. Also, care should be taken not to confuse common root parasites for the fungal structures of VA mycorrhiza.

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.

Condition of the fine roots of sugar maple in different stages of decline

1992 ◽  
Vol 22 (2) ◽  
pp. 264-266 ◽  
Author(s):  
Eric Bauce ◽  
Douglas C. Allen
Keyword(s):  
Fine Roots ◽  
Sugar Maple ◽  
Fine Root ◽  
Fine Root Biomass ◽  
Crown Condition ◽  
Northern Hardwood ◽  
Sugar Maples ◽  
Advanced Stages ◽  
Crown Dieback ◽  
Apparently Healthy

An 85-year-old even-aged northern hardwood stand was studied to elucidate relations between the crown condition of declining sugar maples, Acersaccharum Marsh., and the condition of maple fine roots. Declining sugar maples had lower fine-root biomass and fewer rootlet tips than apparently healthy trees. However, rootlet mortality did not differ significantly between crown dieback classes. Damage to fine roots caused by Ctenophora sp. was significantly greater on trees in advanced stages of decline.

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.

Development of vesicular–arbuscular mycorrhizae in sugar maple (Acer saccharum) and effects of base-cation ammendment on vesicle and arbuscule formation

1993 ◽  
Vol 71 (11) ◽  
pp. 1421-1426 ◽  
Author(s):  
Margaret A. Cooke ◽  
Paul Widden ◽  
Ivan O'Halloran
Keyword(s):  
Acer Saccharum ◽  
Sugar Maple ◽  
Arbuscular Mycorrhizae ◽  
Arbuscular Mycorrhizal ◽  
Base Cation ◽  
Plant Health ◽  
Vesicular Arbuscular Mycorrhizae ◽  
Mycorrhizal Association ◽  
Vesicular Arbuscular ◽  
Hyphal Coils

The development, condition, and incidence of vesicular–arbuscular mycorrhizae of Acer saccharum (sugar maple) seedlings grown in the greenhouse in natural sugar maple forest soil substrate were examined. The effects of the addition of a cation mixture containing calcium, magnesium, and potassium were also studied. The mycorrhizal structures observed were similar to those found in natural field conditions. Mycorrhizae developed intracellularly via hyphal coils, and arbuscules usually developed from these coils, forming arbusculate coils. This development is different from that observed in most annual crop plants. Vesicular–arbuscular mycorrhizal structures appeared within 30 days. The rate of mycorrhizal infection decreased, along with plant health, as the quantity of the added cations was increased, but the amendment did not affect the morphology of the infection. More vesicles were observed in the lowest level of application than in controls, suggesting a stress response and possible relationship between plant health and condition of the mycorrhizal association. Key words: Acer saccharum, development, vesicular–arbuscular mycorrhizae.

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.

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