A role of vesicular-arbuscular (VA) mycorrhizal fungi in facilitating interplant nitrogen transfer

Seedlings of eight half-sib sweetgum (Liquidambarstyraciflua L.) families were grown for 6 months in a fumigated soil mixture, with or without inoculum from a mixture of Glomusmosseae and Glomusetunicatus fungi, at levels of 140, 280, 560, and 1120 kg/ha of 10–10–10 fertilizer. All seedlings received three additions of 187 kg/ha of N during the growing season. Inoculated seedlings had significantly greater biomass, height, and stem diameters at each fertilizer level than nonmycorrhizal control seedlings. Significant differences in growth occurred between families in mycorrhizal plants. However, fertilizer did not significantly affect growth or nutrient uptake of the seedlings. Inoculation with VA mycorrhizal fungi did not increase N, P, K, or Mg concentrations in the leaves, stems, or roots. Leaves of VA mycorrhizal seedlings had higher concentrations of calcium but stems and roots had lower concentrations of this element than the nonmycorrhizal seedlings. Seedlings with endomycorrhizae contained higher absolute quantities of each nutrient simply because of their greater biomass. The results suggest that the role of VA mycorrhizal fungi in the initial growth of sweetgum seedlings may be the result of physiological stimuli other than increased nutrient uptake.

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Vesicular–arbuscular endomycorrhizal associations of some desert plants of Baja California

Canadian Journal of Botany ◽

10.1139/b81-144 ◽

1981 ◽

Vol 59 (6) ◽

pp. 1056-1060 ◽

Cited By ~ 22

Author(s):

Sharon L. Rose

Keyword(s):

Mycorrhizal Fungi ◽

Sonoran Desert ◽

Baja California ◽

Fungal Spores ◽

Desert Plants ◽

Endemic Plants ◽

Mycorrhizal Associations ◽

Glomus Spp ◽

Vesicular Arbuscular ◽

Va Mycorrhizal Fungi

Endemic plants of the Sonoran Desert of Baja California were sampled for mycorrhizal associations. Eight of the 10 plant species examined were colonized by vesicular–arbuscular (VA) mycorrhizal fungi. Soil sievings revealed chlamydospores of three VA mycorrhizal Glomus spp.; G. microcarpus, G. fasciculatus, and G. macrocarpus. At the time of sampling, the populations of VA fungal spores in the soil were low, with one to five chlamydospores per 100 g soil sample.

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The effect of soil pH on the formation of VA mycorrhizas by two species of Glomus

Soil Research ◽

10.1071/sr9850253 ◽

1985 ◽

Vol 23 (2) ◽

pp. 253 ◽

Cited By ~ 47

Author(s):

LK Abbott ◽

AD Robson

Keyword(s):

Soil Ph ◽

Mycorrhizal Fungi ◽

Subterranean Clover ◽

Vesicular Arbuscular ◽

Va Mycorrhizal Fungi ◽

Four Levels ◽

Ph Level ◽

Ph Range ◽

Spread Of Infection ◽

Glomus Sp

Two species of vesicular-arbuscular (VA) mycorrhizal fungi differed in their ability to infect subterranean clover roots when soil pH was changed by liming. In a glasshouse experiment, Glomus fasciculatum infected extensively at each of four levels of soil pH (range 5.3-7.5). Glomus sp. (WUM 16) only infected extensively at the highest pH level. Liming the soil depressed plant growth, but this effect was almost entirely overcome by inoculation with G. fasciculatum. In the second experiment, Glomus sp. (WUM 16) failed to spread from existing infection within roots of subterranean clover when soil pH was 5.3 or lower. The lack of spread of infection was associated with an inability of hyphae of this fungus to grow in the soil used unless it was limed to give a pH at least greater than 5.3.

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Tripartite associations in snowbrush (Ceanothus velutinus): effect of vesicular–arbuscular mycorrhizae on growth, nodulation, and nitrogen fixation

Canadian Journal of Botany ◽

10.1139/b81-006 ◽

1981 ◽

Vol 59 (1) ◽

pp. 34-39 ◽

Cited By ~ 56

Author(s):

S. L. Rose ◽

C. T. Youngberg

Keyword(s):

Host Plant ◽

Mycorrhizal Fungi ◽

Arbuscular Mycorrhizae ◽

Nitrogenase Activity ◽

Mycorrhizal Fungus ◽

Nodule Formation ◽

Nitrogen Fixing ◽

Symbiotic Associations ◽

Vesicular Arbuscular ◽

Va Mycorrhizal Fungi

Symbiotic associations were established between nitrogen-fixing nonleguminous (actinorrhizal) snowbrush (Ceanothus velutinus Dougl.) seedlings and two categories of microorganisms: vesicular–arbuscular (VA) mycorrhizal fungi and a filamentous actinomycete capable of inducing nodule formation. The actinomycete is housed in nodules where fixation of atmospheric dinitrogen occurs and is made available to the host plant; the mycorrhizal fungus is both inter- and intra-cellular within the root tissue and may be found within the nodules. The two major nutrients, N and P, are made available and can be supplied to the host plant by these two symbiotic microorganisms. The root system of snowbrush seedlings was dually colonized by VA mycorrhizal fungi and a nitrogen-fixing actinomycete and the possibility of a direct interaction between the endophytes in the symbioses was investigated. Dually infected plants showed increases in total dry weight of shoots and roots, number of nodules, weight of nodular tissue, as well as higher levels of N, Ca2+, and P, and an increase in nitrogenase activity as measured by acetylene reduction.

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The role of proteins in the nitrogen nutrition of ectomycorrhizal plants. V. Nitrogen transfer in birch (Betula pendula) grown in association with mycorrhizal and non-mycorrhizal fungi

New Phytologist ◽

10.1111/j.1469-8137.1989.tb00309.x ◽

1989 ◽

Vol 112 (1) ◽

pp. 61-68 ◽

Cited By ~ 60

Author(s):

R. A. ABUZINADAH ◽

D. J. READ

Keyword(s):

Mycorrhizal Fungi ◽

Betula Pendula ◽

Nitrogen Nutrition ◽

Nitrogen Transfer

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Introduction of vesicular arbuscular mycorrhizal fungi into agricultural soils

Australian Journal of Agricultural Research ◽

10.1071/ar9830741 ◽

1983 ◽

Vol 34 (6) ◽

pp. 741 ◽

Cited By ~ 30

Author(s):

LK Abbott ◽

AD Robson ◽

IR Hall

Keyword(s):

Mycorrhizal Fungi ◽

Agricultural Soils ◽

Subterranean Clover ◽

Arbuscular Mycorrhizal ◽

Temporary Increase ◽

Indigenous Species ◽

Previous Survey ◽

Rate Of Development ◽

Vesicular Arbuscular ◽

Va Mycorrhizal Fungi

Two species of vesicular arbuscular (VA) mycorrhizal fungi were introduced into agricultural soils at four field sites. Three sites were chosen, on the basis of a previous survey, to give a range in the expected extent and rate of mycorrhizal formation by the indigenous fungi. The fourth site had recently been cleared of natural vegetation and ploughed. The success of inoculation with Glomus fasciculatum and G. monosporum was measured by estimating the extent of mycorrhizas formed by the inoculant fungi and by recording growth of subterranean clover. The effects of inoculating with these two mycorrhizal fungi on the development of mycorrhizas formed by the indigenous fungi were also followed in detail. At two sites, infection by G. fasciculatum was increased in the plots where this species was added in the inoculum. Growth was temporarily enhanced after inoculation with G. fasciculatum at one of these sites. This corresponded with a temporary increase in the percentage of root length infected as a result of inoculation. Plants grown at the two sites where G. fasciculatum became established had a slower rate of development of infection by the indigenous VA mycorrhizal fungi compared with that formed by the indigenous species at the other two sites.

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The physiology of vesicular–arbuscular endomycorrhizal symbiosis

Canadian Journal of Botany ◽

10.1139/b83-105 ◽

1983 ◽

Vol 61 (3) ◽

pp. 944-963 ◽

Cited By ~ 233

Author(s):

D. S. Hayman

Keyword(s):

Mycorrhizal Fungi ◽

Biological Diversity ◽

Copper Ions ◽

Root Surface ◽

P Uptake ◽

Mycorrhizal Symbiosis ◽

Va Mycorrhizae ◽

Wide Range ◽

Vesicular Arbuscular ◽

Va Mycorrhizal Fungi

The enhanced growth of plants infected by vesicular–arbuscular (VA) mycorrhizal fungi results primarily from improved uptake of soil phosphate. Extra phosphate reaches the root through the fungal hyphae, which tap the soluble P in soil beyond the phosphate-depletion zone near the root surface. This mechanism can explain the many corrrelations between root geometry and mycotrophy and other nutritional effects of VA mycorrhizae such as increased uptake of zinc and copper ions. Recently VA mycorrhizae have been shown to increase the levels of chlorophyll and some hormones in plants and to alleviate water stress. Legumes are now receiving considerable attention because VA mycorrhiza affects nitrogen fixation in them indirectly by its action on P uptake. In this review the physiology of the VA mycorrhizal symbiosis is discussed in categories reflecting successive stages in its formation and function: (i) activation of the VA mycorrhizal propagules; (ii) penetration and initial infection of the host plant; (iii) spread of infection in roots; (iv) response of the plant; the components and mechanisms of VA mycorrhizal systems; (v) benefits to the fungus; carbon sinks; and (vi) imbalances in the symbiosis. It is suggested that studies on the physiological complexities of VA mycorrhizal associations should take more account of the biological diversity of VA mycorrhizal fungi and the wide range of host–endophyte–soil specificities.

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Ecological consequences of arthropod grazing on VA mycorrhizal fungi

Proceedings of the Royal Society of Edinburgh Section B Biological Sciences ◽

10.1017/s0269727000007077 ◽

1988 ◽

Vol 94 ◽

pp. 25-32 ◽

Cited By ~ 2

Author(s):

T. P. McGonigle ◽

A. H. Fitter

Keyword(s):

Mycorrhizal Fungi ◽

Arbuscular Mycorrhizal ◽

Holcus Lanatus ◽

Feeding Damage ◽

Field Plot ◽

Paper Briefly ◽

Sterile Soil ◽

Grassland Soil ◽

Vesicular Arbuscular ◽

Va Mycorrhizal Fungi

SynopsisSoil Collembola may be partially responsible for observed reductions in effectiveness of vesicular-arbuscular mycorrhizal (VAM) associations in the field, compared with sterile soil experiments. Feeding damage to hyphae in soil is envisaged as a mechanism by which translocation of phosphorous from beyond root depletion zones to the plants is reduced. Previous work has demonstrated such effects in pots and in a cultivated field plot, and direct observation of feeding has been made. This paper briefly reviews this evidence and presents an experiment in which insecticide reduced the density of Collembola in a seminatural grassland soil, and increased phosphorus inflow into roots of Holcus lanatus. In addition, survey data are reported which show that hyphal grazing is ecologically feasible, as Collembola and infected roots are spatially associated with one another in the soil profile. It is suggested that hyphal grazing by these arthropods has important consequences for VAM function in natural vegetation systems.

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Vesicular-arbuscular mycorrhizae of Easter lily in the northwestern United States

Canadian Journal of Microbiology ◽

10.1139/m77-239 ◽

1977 ◽

Vol 23 (12) ◽

pp. 1663-1668 ◽

Cited By ~ 5

Author(s):

R. N. Ames ◽

R. G. Linderman

Keyword(s):

Root System ◽

Mycorrhizal Fungi ◽

Arbuscular Mycorrhizae ◽

Lilium Longiflorum ◽

Growing Season ◽

Fungal Species ◽

Easter Lily ◽

Vesicular Arbuscular ◽

Va Mycorrhizal Fungi ◽

Isolated Species

The vesicular-arbuscular (VA) mycorrhizal fungi of commercially grown Easter lily (Lilium longiflorum Thunb.) were studied. Soil and root samples were collected monthly from March through September 1975 from five fields in the coastal area of southern Oregon and northern California. Soil seivings were inoculated onto clover, onion, and lily to cause infections resulting in the production of many new mycorrhizal spores facilitating identification. Four VA mycorrhizal species were found: Acaulospora trappei, A. elegans, Glomus monosporus, and G. fasciculatus. All four VA species infected Easter lily, clover, and onion. Acaulospora trappei and G. fasciculatus were the most commonly isolated species from all five fields.Mycorrhizal infections in roots of field-grown lilies were sparse and presumably young in March and gradually increased in size and number until September when bulbs were harvested. Over 75% of each root system became infected with mycorrhizae in fields with all four fungal species, and those levels were reached by July. In fields with only two mycorrhizal species, usually 50% or less of each root system was infected, even by the end of the growing season.

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Formation and Structure of Mycorrhizas of Seedlings of Coachwood (Ceratopetalum apetalum)

Australian Journal of Botany ◽

10.1071/bt9920291 ◽

1992 ◽

Vol 40 (3) ◽

pp. 291 ◽

Cited By ~ 11

Author(s):

PA Mcgee ◽

JH Furby

Keyword(s):

Flux Density ◽

Mycorrhizal Fungi ◽

Negative Response ◽

Photon Flux ◽

Photon Flux Density ◽

Va Mycorrhizas ◽

Hartig Net ◽

Vesicular Arbuscular ◽

Va Mycorrhizal Fungi ◽

Fungal Associations

The mycorrhizas of seedlings of coachwood (Ceratopetalum apetalum) were examined. When the host was grown under increased photon flux density infections of both vesicular-arbuscular (VA) and a sheathing association were extended. Paris type VA mycorrhizas were observed, though arbuscules and vesicles were rare. Hyphae of VA mycorrhizal fungi appeared to degenerate when under the sheathing association. The sheathing association was characterised by thin mantles and no Hartig net. An electron-dense bilayer formed over hyphae in the sheath and hyphae were surrounded by a fibrillar matrix. Beneath the sheath, the walls of the epidermis were thickened and fibrillar. Lignin and suberin were present in the walls of cells of the hypodermis and absent in the epidermis. No evidence was found that the fungal associations induced a negative response from the host. While the structure of the mycorrhizas was unusual, the sheathing association was believed to be a variant of typical ectomycorrhizas.

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