Mycorrhizal associations of some actinomycete nodulated nitrogen-fixing plants

1980 ◽  
Vol 58 (13) ◽  
pp. 1449-1454 ◽  
Author(s):  
Sharon L. Rose
Keyword(s):  
United States ◽  
Mycorrhizal Fungi ◽  
The United States ◽  
Flowering Plants ◽  
Atmospheric Nitrogen ◽  
Nitrogen Fixing ◽  
Mycorrhizal Associations ◽  
Vesicular Arbuscular ◽  
Distributional Patterns ◽  
Va Mycorrhizal Fungi

Flowering plants that fix atmospheric nitrogen in actinomycete-induced nodules were sampled for mycorrhizal associates. Twenty-five species from seven families (Betulaceae, Casuarinaceae, Myricaceae, Rhamnaceae, Rosaceae, Elaeagnaceae, and Datiscaceae) were examined. Samples included were from the United States, Japan, and England.Both mycorrhizae and actinomycete-induced nitrogen-fixing nodules were present on: (i) four species of Alnus, (ii) two species of Casuarina, (iii) eight species of Ceanothus, (iv) four species of Myrica, (v) and one species each of Shepherdia, Hippophae, Cercocarpus, Dryas, Purshia, Comptonia, and Datisca. Soil sieving revealed species of the following genera of vesicular–arbuscular (VA) mycorrhizal fungi: Gigaspora, Glomus, Acaulospora, Entrophospora, and three undescribed taxa soon to be described. Spores of species in the first three genera of fungi were found most frequently from soil sievings. The VA mycorrhizal fungi exhibited distinct distributional patterns when associated with nonleguminous nitrogen-fixing hosts in different habitats. The ectomycorrhizae were not characterized.

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

1981 ◽  
Vol 59 (6) ◽  
pp. 1056-1060 ◽  
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.

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

1981 ◽  
Vol 59 (1) ◽  
pp. 34-39 ◽  
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.

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

Soil Research ◽  
1985 ◽  
Vol 23 (2) ◽  
pp. 253 ◽  
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.

Mycorrhizal fungi associated with Festuca in the western United States and Canada

1978 ◽  
Vol 56 (14) ◽  
pp. 1691-1695 ◽  
Author(s):  
Randolph J. Molina ◽  
James M. Trappe ◽  
Gerald S. Strickler
Keyword(s):  
United States ◽  
Mycorrhizal Fungi ◽  
Arbuscular Mycorrhizal ◽  
Western United States ◽  
Individual Plant ◽  
Mycorrhizal Infection ◽  
Acaulospora Laevis ◽  
Fine Root Length ◽  
Vesicular Arbuscular ◽  
Festuca Idahoensis

Vesicular–arbuscular mycorrhizal infection and associated mycorrhizal fungi were examined for Festuca viridula, Festuca idahoensis, Festuca scabrella, Festuca thurberi, Festuca ovina, and Festuca arizonica occurring in Festuca-dominated grasslands in the western United States and Canada. All plants were mycorrhizal. Nearly all had mycorrhizal infection in 75% or more of their fine root length. Although levels of infection were consistently high, spore numbers were generally low. No differences in the degree of infection between Festuca species or habitats were observed.Eleven mycorrhizal fungi were identified and ranked by decreasing frequency as follows: Glomus fasciculatus, Glomus tenuis, Gigaspora calospora, Acaulospora laevis, Glomus macrocarpus var. macrocarpus, Glomus microcarpus, Acaulospora scrobiculata, Glomus mosseae, Glomus macrocarpus var. geosporus, Sclerocystis rubiformis, and an unidentified Acaulospora species. It was common to find two or more species infecting an individual plant. The mean number of fungal associates per community site ranged from 2.7 species for F. idahoensis to 5.0 species for F. arizonica. We found no evidence for specificity of any of the mycorrhizal fungi for any particular Festuca host.

Vesicular–arbuscular mycorrhiza influence growth but not mineral concentrations in seedlings of eight sweetgum families

1979 ◽  
Vol 9 (2) ◽  
pp. 218-223 ◽  
Author(s):  
R. C. Schultz ◽  
P. P. Kormanik ◽  
W. C. Bryan ◽  
G. H. Brister
Keyword(s):  
Arbuscular Mycorrhiza ◽  
Nutrient Uptake ◽  
Mycorrhizal Fungi ◽  
Growing Season ◽  
Initial Growth ◽  
Soil Mixture ◽  
Vesicular Arbuscular ◽  
Va Mycorrhizal Fungi ◽  
Mineral Concentrations

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.

scholarly journals Conditional vulnerability of plant diversity to atmospheric nitrogen deposition across the United States

2016 ◽  
Vol 113 (15) ◽  
pp. 4086-4091 ◽  
Author(s):  
Samuel M. Simkin ◽  
Edith B. Allen ◽  
William D. Bowman ◽  
Christopher M. Clark ◽  
Jayne Belnap ◽  
...  
Keyword(s):  
United States ◽  
Species Richness ◽  
Plant Species ◽  
Plant Species Richness ◽  
The United States ◽  
N Deposition ◽  
Soil Conditions ◽  
Atmospheric Nitrogen ◽  
General Response ◽  
Negative Relationships

Atmospheric nitrogen (N) deposition has been shown to decrease plant species richness along regional deposition gradients in Europe and in experimental manipulations. However, the general response of species richness to N deposition across different vegetation types, soil conditions, and climates remains largely unknown even though responses may be contingent on these environmental factors. We assessed the effect of N deposition on herbaceous richness for 15,136 forest, woodland, shrubland, and grassland sites across the continental United States, to address how edaphic and climatic conditions altered vulnerability to this stressor. In our dataset, with N deposition ranging from 1 to 19 kg N⋅ha−1⋅y−1, we found a unimodal relationship; richness increased at low deposition levels and decreased above 8.7 and 13.4 kg N⋅ha−1⋅y−1 in open and closed-canopy vegetation, respectively. N deposition exceeded critical loads for loss of plant species richness in 24% of 15,136 sites examined nationwide. There were negative relationships between species richness and N deposition in 36% of 44 community gradients. Vulnerability to N deposition was consistently higher in more acidic soils whereas the moderating roles of temperature and precipitation varied across scales. We demonstrate here that negative relationships between N deposition and species richness are common, albeit not universal, and that fine-scale processes can moderate vegetation responses to N deposition. Our results highlight the importance of contingent factors when estimating ecosystem vulnerability to N deposition and suggest that N deposition is affecting species richness in forested and nonforested systems across much of the continental United States.

MYCORRHIZAL FUNGI AT EIGHTEEN APPLE ROOTSTOCK PLANTINGS IN THE UNITED STATES

1985 ◽  
Vol 100 (3) ◽  
pp. 379-391 ◽  
Author(s):  
DIANE DOUD MILLER ◽  
PAUL A. DOMOTO ◽  
CHRISTOPHER WALKER
Keyword(s):  
United States ◽  
Mycorrhizal Fungi ◽  
The United States ◽  
Apple Rootstock

Introduction of vesicular arbuscular mycorrhizal fungi into agricultural soils

1983 ◽  
Vol 34 (6) ◽  
pp. 741 ◽  
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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