Bacteria and actinomycetes associated with pot cultures of vesicular–arbuscular mycorrhizas

1987 ◽  
Vol 33 (12) ◽  
pp. 1069-1073 ◽  
Author(s):  
Jean Secilia ◽  
D. J. Bagyaraj
Keyword(s):  
Mycorrhizal Fungi ◽  
Xanthomonas Campestris ◽  
Mycorrhizal Fungus ◽  
Arbuscular Mycorrhizas ◽  
Bacterial Populations ◽  
Phytopathogenic Bacterium ◽  
Nitrogen Fixers ◽  
Acaulospora Laevis ◽  
Vesicular Arbuscular ◽  
Va Mycorrhizal Fungi

The bacteria and actinomycetes associated with pot cultures of the vesicular–arbuscular (VA) mycorrhizal fungi Glomus fasciculatum, Gigaspora margarita, Acaulospora laevis, Sclerocystis dussii, and of a control without VA mycorrhizal fungus were studied. Total bacterial populations and numbers of nitrogen fixers were significantly higher in the pot cultures of G. fasciculatum, G. margarita, and S. dussii. There were more gram-negative bacteria in these three pot cultures. Spore formers decreased and urea hydrolysers increased in all four pot cultures. The pot cultures of A. laevis harboured fewer bacteria compared with the control. The occurrence of amino acid requiring bacteria increased in all the pot cultures, except that of A. laevis. Pot cultures of G. fasciculatum and A. laevis had significantly more actinomycetes than the control. Streptomyces, series Rectus flexibilis, was selectively stimulated. These two pot cultures also had more actinomycetes antagonistic to the pathogens Fusarium solani and Pseudomonas solanacearum than the control. Glomus margarita pot cultures harboured more actinomycetes antagonistic to the phytopathogenic bacterium Xanthomonas campestris pv. vignicola.

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.

Spore Populations and Infectivity of Vesicular Arbuscular Mycorrhizal Fungi in New South Wales

1979 ◽  
Vol 27 (3) ◽  
pp. 227 ◽  
Author(s):  
DS Hayman ◽  
GE Stovold
Keyword(s):  
Mycorrhizal Fungi ◽  
New South ◽  
New South Wales ◽  
Arbuscular Mycorrhizal ◽  
South Wales ◽  
Acaulospora Laevis ◽  
Native Grassland ◽  
Vesicular Arbuscular ◽  
Va Mycorrhizal Fungi ◽  
Dry Soil

Spores of vesicular arbuscular (VA) mycorrhizal fungi were found in all 73 soil samples collected from different parts of New South Wales. Their numbers ranged widely from site to site (from 2 to 1952 spores per 100 g dry soil) and varied considerably for the same crop at different sites (e.g. from 47 to 464 spores per 100 g dry soil for wheat). In general there were more spores in agricultural than in native grassland-bush soils. Of the eight species found, Acaulospora laevis and Glomus mosseae were the commonest. Small spores of the Glomus fasciculatus and G. microcarpus groups were also frequent but Gigaspora spp. were fairly rare. Usually more than two VA species occurred at each site. The infectivity of the VA population in soil, assayed by measuring the rate of mycorrhizal develop- ment in clover seedlings, did not correlate with spore numbers.

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.

Susceptibility of barley cultivars to vesicular-arbuscular mycorrhizal fungi

1995 ◽  
Vol 75 (1) ◽  
pp. 269-275 ◽  
Author(s):  
S. M. Boyetchko ◽  
J. P. Tewari
Keyword(s):  
Mycorrhizal Fungi ◽  
Mycorrhizal Fungus ◽  
Arbuscular Mycorrhizal ◽  
Growth And Yield ◽  
Vam Fungi ◽  
University Of Alberta ◽  
Barley Cultivars ◽  
Vesicular Arbuscular ◽  
Glomus Species ◽  
The University

The relative susceptibility of selected barley cultivars produced in western Canada to vesicular-arbuscular mycorrhizal (VAM) fungi under field and greenhouse conditions was evaluated in this study. Cultivars tested under field conditions at the University of Alberta and Lacombe research stations showed no significant differences in VAM colonization of barley roots; colonization was light. Greenhouse trials at the University of Alberta with eight cultivars inoculated with individual mycorrhizal species illustrated significant differences among the barley cultivars in their reactions to Glomus dimorphicum, G. intraradices, and G. mosseae. Distinct differences were observed in the ability of each Glomus species to colonize the barley cultivars. The VAM fungi increased growth and yield in some cultivars, depending on the Glomus species. This study indicates that a degree of host-specificity exists in VAM fungi and that the host-mycorrhizal fungus genotypes may influence the effectiveness of the symbiosis. Key words: Barley, cultivars, susceptibility, VA mycorrhizal fungi

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.

Ecological interaction of little bluestem and vesicular–arbuscular mycorrhizal fungi

1984 ◽  
Vol 62 (11) ◽  
pp. 2272-2277 ◽  
Author(s):  
Laura A. Dickman ◽  
Anthony E. Liberta ◽  
Roger C. Anderson
Keyword(s):  
Soil Moisture ◽  
Mycorrhizal Fungi ◽  
Arbuscular Mycorrhizal ◽  
Schizachyrium Scoparium ◽  
Sample Collection ◽  
Little Bluestem ◽  
Acaulospora Laevis ◽  
Vesicular Arbuscular ◽  
Vam Colonization ◽  
Hill Prairie

The percentage of vesicular–arbuscular mycorrhizal (VAM) colonization of little bluestem (Schizachyrium scoparium) (Michx.) Nash.) and VAM spore populations in the rhizosphere of little bluestem from four prairie areas in Illinois were studied. At Goose Lake Prairie, a significant positive correlation (r = 0.77, p < 0.01) was found between soil moisture and density of VAM spores, but soil moisture and percent VAM colonization were not significantly correlated at any of its sites. Percentage of VAM colonization tended to be higher at study areas where little bluestem was a dominant species. However, spore numbers and abundance of little bluestem tended to be inversely related. Colonization decreased from May to July at all areas and this trend frequently continued into September. Month of sample collection had no significant effect on spore numbers except at Reavis Hill Prairie. The endophyte isolated at all areas was Glomus fasciculatum (Thaxter sensu Gerd.) Gerd. & Trappe. Other species, such as Gigaspora heterogama (Nicol. & Gerd.) Gerd. & Trappe and Acaulospora laevis Gerd. & Trappe, were more restricted in their distribution.

Effects of vesicular-arbuscular mycorrhizal infection in first, second and third cereal crops

1985 ◽  
Vol 105 (3) ◽  
pp. 631-647 ◽  
Author(s):  
J. G. Buwalda ◽  
D. P. Stribley ◽  
P. B. Tinker
Keyword(s):  
Spring Wheat ◽  
Mycorrhizal Fungi ◽  
Dry Matter ◽  
Arbuscular Mycorrhizal Fungus ◽  
Mycorrhizal Fungus ◽  
Arbuscular Mycorrhizal ◽  
Residual Effects ◽  
Cereal Crops ◽  
Mycorrhizal Infection ◽  
Vesicular Arbuscular

SUMMARYThe effects of inoculation with the vesicular-arbuscular mycorrhizal fungus Olomics mosseae(Nicolson & Gerdemann) Gerdemann and Trappe, fumigation of soil with methyl bromide, and addition of superphosphate (up to 60 kg P/ha) on growth and phosphorus nutrition of spring wheat (Triticum aestivum L. cv. Highbury) were investigated in two experiments (in 1980 and 1981 respectively) on plots that had been fallowed and recently limed.Fumigation severely reduced natural levels of infection, and slightly reduced yield of above-ground dry matter in both years. In 1981 a decrease in grain yield of about 25% was accompanied by an increase in growth of straw. Plants on fumigated plots contained appreciable amounts of bromine in shoot tissue.Inoculation increased and added P decreased infection in all treatments. In 1980 inoculation had little effect on above-ground dry matter, but it increased concentration of P in shoots especially on plots without added P. In 1981 added inoculum increased yield of grain on fumigated plots by about 0·75 t/ha at all levels of added P, but had little effect on non-fumigated plots, though responses in grain production to added P were similar with and without fumigation. Increases in yield resulting from inoculation were generally accompanied by increases in concentration of P in plant tissue.Winter barley was sown on the plots after their use for spring wheat, without further application of the fumigation, inoculation or phosphorus treatments used in those experiments, to determine any residual effects on mycorrhizal infection and on growth. The levels of mycorrhizal infection on non-fumigated, inoculated plots were relatively constant in successive crops, although numbers of propagules of mycorrhizal fungi increased significantly with time for all treatments. Infection levels on fumigated and non-inoculated plots increased in successive crops, so that the relative effects of fumigation and of inoculation declined with time.The effects of inoculation on infection levels persisted for longer than those on yields, suggesting that maximum effects of mycorrhizal infection on growth did not require the maximum levels of infection found in the roots. Harvest yields continued to respond to applied phosphorus even when uniformly high levels of infection had been established, suggesting that the ability of the root system to absorb phosphate was not greatly increased by mycorrhizal infection.

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