Ecological consequences of arthropod grazing on VA mycorrhizal fungi

1988 ◽  
Vol 94 ◽  
pp. 25-32 ◽  
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.

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.

The Effect of Surface Mining on the Infectivity of Vesicular-Arbuscular Mycorrhizal Fungi

1987 ◽  
Vol 35 (6) ◽  
pp. 641 ◽  
Author(s):  
DA Jasper ◽  
AD Robson ◽  
LK Abbott
Keyword(s):  
Mycorrhizal Fungi ◽  
Surface Mining ◽  
Subterranean Clover ◽  
Arbuscular Mycorrhizal ◽  
Mining Operation ◽  
Soil Disturbance ◽  
Inoculum Potential ◽  
Vesicular Arbuscular ◽  
Va Mycorrhizal Fungi ◽  
Mine Sites

We tested the hypothesis that soil disturbance associated with mining will reduce the infectivity of propagules of vesicular-arbuscular (VA) mycorrhizal fungi to different extents, depending on the mining operation and the environment. At each of four mine sites, the infectivity of VA mycorrhizal fungi was estimated in soil from native vegetation, disturbed topsoil and revegetated soil. Infectivity was measured using subterranean clover and Acacia species as bioassay plants. In a second experiment the effects of soil disturbance and soil storage on infectivity of VA mycorrhizal fungi were measured separately. Topsoil disturbance decreased the number of spores or the number of spore types that could be isolated from the soil, and reduced or delayed formation of VA mycorrhizas. Glasshouse treatments indicated that both disturbance and a period of storage without plant growth contributed to the loss in infectivity of propagules of VA mycorrhizal fungi. After 4-5 years of revegetation, the number of infective propagules appears to be restored to a level equivalent to that of undisturbed soils. The possibility of improving revegetation by increasing the inoculum potential of disturbed soils needs to be investigated.

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.

The effect of long-term applications of phosphorus fertilizer on populations of vesicular-arbuscular mycorrhizal fungi in pastures

1992 ◽  
Vol 43 (5) ◽  
pp. 1131 ◽  
Author(s):  
BD Thomson ◽  
AD Robson ◽  
LK Abbott
Keyword(s):  
Mycorrhizal Fungi ◽  
Indirect Evidence ◽  
Arbuscular Mycorrhizal ◽  
Mycorrhizal Colonization ◽  
Inoculum Potential ◽  
Field Site ◽  
Vesicular Arbuscular ◽  
P Fertilizer ◽  
Va Mycorrhizal Fungi ◽  
Selection Of

We assessed whether 6-year-old applications of phosphorus (P) fertilizer to a previously unfertilized field site resulted in the selection of populations of vesicular-arbuscular (VA) mycorrhizal fungi that were more 'tolerant' of added P than the original VA mycorrhizal population at the site. In 1977, four rates of P (0, 49, 97 and 200 kg P/ha) were applied to a field site at Mt Barker, Western Australia. In 1983, either no P or a rate of P sufficient for maximum plant growth (352 kg P/ha) was applied to each of these plots and the formation of spores and colonization of roots by VA mycorrhizal fungi were examined in the following 3 years. Residual P from fertilizers applied in 1977 increased both the percentage of root length colonized and the length of root colonized by VA mycorrhizal fungi in 1983, 1984 and 1985. Colonization by 'medium hyphae' Glomus spp., Acaulospora laevis Gerd. and Trappe and fine endophyte increased in response to the 1977 applications of P. By contrast, colonization by Scutellospora calospora (Nicol. and Gerd.) Walker and Sanders decreased with the 1977 applications of P. Application of an adequate rate of P to the field plots in 1983 generally decreased the development of VA mycorrhizal infection in plots, to a greater extent where larger rates of P had previously been applied in 1977. We attributed this effect to higher initial levels of mycorrhizal colonization in the plots which received larger rates of P in 1977. The 1977 applications of P are unlikely to have resulted in the selection of strains of VA mycorrhizal fungi that are less tolerant of added P than the strains present in the unfertilized plots. There was a common relationship between VA mycorrhizal colonization and the residual value of the P applications which provided indirect evidence that there was no change in the P-tolerance of the indigenous VA mycorrhizal population in response to P applied in 1977. Interpretation of the effects of the 1977 and 1983 applications of P on VA mycorrhizal colonization was compounded by the effects these applications of P had on the botanical composition of the pasture and also on the inoculum potential in each plot. Spores of A. laevis and S. calospora were recovered from each field plot. The number of spores of A. laevis increased in response to P applied in 1977 and generally decreased in response to P applied in 1983. These effects could be directly related to the effects the 1977 and 1983 applications of P had on the length of root colonized by A. laevis in the preceding growing season.

Association of vesicular–arbuscular mycorrhizal fungi with the moss Funaria hygrometrica

1980 ◽  
Vol 58 (17) ◽  
pp. 1898-1904 ◽  
Author(s):  
Jennifer L. Parke ◽  
R. G. Linderman
Keyword(s):  
Mycorrhizal Fungi ◽  
Leaf Tissue ◽  
Soil Surface ◽  
Arbuscular Mycorrhizal ◽  
Funaria Hygrometrica ◽  
Vesicular Arbuscular ◽  
Companion Plant ◽  
Va Mycorrhizal Fungi ◽  
Hyphal Coils ◽  
Companion Plants

Reports on the mycorrhizal status of mosses have been scanty and inconclusive. We observed hyphae and vesicles resembling structures of vesicular–arbuscular (VA) mycorrhizal fungi within the moss Funaria hygrometrica Hedw. growing on the soil surface of asparagus – Glomus epigaeus pot cultures. Controlled-environment experiments to determine whether moss is a potential host for VA fungi were conducted by inoculating moss cultures, asparagus plants, or combinations of moss and asparagus plants with chlamydospores of G. epigaeus. Examination of cleared and stained asparagus roots and moss plants 10 weeks after addition of G. epigaeus spores revealed typical arbuscules, vesicles, and hyphal coils in roots of asparagus grown alone or in combination with moss; hyphae, vesicles, and spores were seen in moss plants, but only in those grown with asparagus "companion" plants. Glomus epigaeus colonization was widespread in moss stem and leaf tissue, and spore production was most prolific in senescent tissues. Similar endophytic structures and abundant sporulation occurred in the moss layer of G. mosseae and G. fasciculalus moss-companion plant pot cultures. Although the Funaria–VA fungus association is apparently not a mutualistic one, the system may have ecological significance as well as potential for production of VA inoculum.

Occurrence of Vesicular-Arbuscular Mycorrhizal Fungi in Alberta, Canada

1993 ◽  
Vol 48 (11-12) ◽  
pp. 923-929 ◽  
Author(s):  
S. M. Boyetchko ◽  
J. P. Tewari
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Mycorrhizal Fungi ◽  
Arbuscular Mycorrhizal ◽  
Fungal Species ◽  
Glomus Aggregatum ◽  
X Ray ◽  
Vesicular Arbuscular ◽  
Spore Walls ◽  
Scanning Electron

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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