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

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.

2003 ◽  
Vol 83 (4) ◽  
pp. 969-976 ◽  
Author(s):  
J. R. Moyer ◽  
M. J. Clapperton ◽  
A. L. Boswall

Experiments were established on irrigated land at Lethbridge, Alberta, to determine the effect of timing and method of alfalfa (Medicago sativa L.) termination on weed abundance, soil moisture and N content, cereal yield and colonization of roots by vesicular arbuscular mycorrhizal (VAM) fungi. Alfalfa growth was terminated using no, minimum, and conventional tillage in either late summer, early fall, or spring. Herbicide was applied or tillage was used to control volunteer alfalfa, dandelion (Taraxacum officinale Weber), stinkweed (Thlaspi arvense L.), and kochia [Kochia scoparia (L.) Schrader] before seeding cereals. Dandelion and volunteer alfalfa density tended to be greatest after no-tillage treatments, and poor in-crop alfalfa control likely reduced cereal yields in no-tillage plots. In contrast, the major in-crop broadleaf weed, redroot pigweed (Amaranthus retroflexus L.), was most dense (7 plants m-2) in tilled plots. Both wheat (Triticum aestivum L.) and barley (Hordeum vulgare L.) yields were reduced 9 to 12% after alfalfa termination with no-tillage treatments compared with minimum or conventional tillage. In spring, after seeding, available soil N content averaged 138, 101 and 79 kg ha-1 for conventional-, minimum-and no-tillage plots, respectively; however, fall no-tillage treatments seemed to supply sufficient N for wheat and barley. Soil moisture content tended to be similar after all termination treatments. Wheat and barley responded differently to time and method of termination in terms of seedling root length and colonization by VAM fungi. The percentage of root colonized by VAM fungi was greater on both barley and wheat in no-tillage compared to cultivated treatments. It may be possible to have similar wheat and barley yields after no tillage and tilled alfalfa termination if no-tillage termination is initiated in fall and effective incrop herbicides are used for volunteer alfalfa and dandelion control. Key words: Alfalfa termination, no-tillage, N, vesicular arbuscular mycorrhizal fungi, weed density


1978 ◽  
Vol 56 (14) ◽  
pp. 1691-1695 ◽  
Author(s):  
Randolph J. Molina ◽  
James M. Trappe ◽  
Gerald S. Strickler

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.


HortScience ◽  
2000 ◽  
Vol 35 (3) ◽  
pp. 463A-463
Author(s):  
Rhoda Burrows ◽  
Francis Pfleger

Growing a plant host in association with other plant species (i.e., increasing diversity) changes the composition of the associated arbuscular–mycorrhizal (AM) fungal community. We tested whether this alteration in the fungal community causes significant differences in the growth of Schizachyrium scoparium L. (Little Bluestem, a C4 grass) or Lespedeza capitata L. (Bush clover, a legume). Seedlings were transplanted into pasteurized soil inoculated with soil from monoculture plots of Schizachyrium or Lespedeza, respectively, vs. plots containing one, seven, or 15 additional plant species. Soil washes from a composite of the plots were added to all pots, including non-inoculated controls, to reduce differences in the non-AM microbial communities. Spore counts of the inoculum from Lespedeza plots showed increasing numbers of AM fungal spores and species richness with increasing plant diversity; this was not true with the Schizachyrium plots, possibly because Schizachyrium may be a better host to more species of AM fungi than Lespedeza. Both Schizachyrium and Lespedeza responded to inoculation with increased growth compared to non-inoculated controls. Tissue analyses of both species showed that inoculation increased the percentage of Cu, and lowered the percentage of Mn compared to control plants. Schizachyrium showed no significant differences in growth due to inoculum source (1-, 2-, 8-, or 16-species plots); while Lespedeza showed increases in root and shoot weights with increasing source-plot diversity.


1988 ◽  
Vol 66 (4) ◽  
pp. 757-761 ◽  
Author(s):  
Lisa J. Cerligione ◽  
Anthony E. Liberta ◽  
Roger C. Anderson

Nonmycorrhizal little-bluestem plants grown in sterile soil and mycorrhizal plants grown in unsterilized soil were experimentally subjected to varied soil moisture conditions that ranged from saturation for 12 h followed by drainage for 48 h to allowing soil to dry to permanent wilting point and returning it to field capacity 72 h later. Nonmycorrhizal plants produced significantly (p < 0.05) greater root and shoot biomass, had lower root/shoot ratios, and produced more flowering culms than mycorrhizal plants. However, mycorrhizal plants had significantly higher tissue concentrations of phosphorus, calcium, zinc, iron, copper, aluminum, and sodium and lower concentrations of potassium amd manganese. There was a decrease in percent colonization as soil water availability decreased.


1979 ◽  
Vol 27 (3) ◽  
pp. 227 ◽  
Author(s):  
DS Hayman ◽  
GE Stovold

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.


1993 ◽  
Vol 48 (11-12) ◽  
pp. 923-929 ◽  
Author(s):  
S. M. Boyetchko ◽  
J. P. Tewari

Abstract Three V A mycorrhizal fungal species were isolated from soils in Alberta, Canada and examined by scanning electron microscopy and energy-dispersive X-ray microanalysis. Mature spores of Glomus aggregatum developed an outer hyaline wall which contained lower levels of calcium than the middle wall. Examination of G. pansihalos spores revealed a lower level of calcium in the outer evanescent wall as compared to the ornamented wall. When spores of Entrophospora infrequens were examined, the wall of the vesicle was found to contain similar levels of calcium as the ornamented wall of the spore. The significance of the results concerning the presence of calcium in mycorrhizal spore walls is discussed, as is the occurrence of the mycorrhizal species.


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