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.

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.

scholarly journals Effects of Bifenthrin on Mycorrhizal Colonization and Growth of Corn

2009 ◽  
Vol 19 (4) ◽  
pp. 809-812 ◽  
Author(s):  
Lea Corkidi ◽  
Jeff Bohn ◽  
Mike Evans
Keyword(s):  
Mycorrhizal Fungi ◽  
Arbuscular Mycorrhizal ◽  
Dry Weight ◽  
Mycorrhizal Colonization ◽  
Inoculum Potential ◽  
Red Imported Fire Ant ◽  
Negative Effects ◽  
Mycorrhizal Inoculum Potential ◽  
Shoot Dry Weight ◽  
Total Percentage

The insecticide bifenthrin is a synthetic pyrethroid required by regulation for the production of nursery crops to suppress the red imported fire ant (Solenopsis invicta) in Orange and Riverside counties in California. We conducted a greenhouse experiment to analyze the effects of different rates of bifenthrin on the growth and mycorrhizal colonization of ‘Silver Queen’ corn (Zea mays) inoculated with VAM 80®, a mycorrhizal inoculum with spores, hyphae, and root pieces colonized by Glomus spp., used to inoculate California native plants in containers. Corn was used because it is the standard indicator plant used for mycorrhizal inoculum potential assays and it is a good host for arbuscular mycorrhizal fungi propagation. The application of bifenthrin had no detrimental effects on mycorrhizal colonization of corn. There were no significant differences in the root length colonized by arbuscules, vesicles, or in the total percentage of mycorrhizal colonization obtained in the plants grown with the different bifenthrin rates 6 weeks after transplanting. However, there were significant interactions on the effects of bifenthrin and mycorrhizal colonization on plant growth. The addition of 12, 15, and 25 ppm of bifenthrin reduced corn biomass of nonmycorrhizal plants, but had no effect on the growth of mycorrhizal plants. There were no significant differences between the mycorrhizal and nonmycorrhizal plants grown with 0, 10, and 12 ppm of bifenthrin. In contrast, inoculation with VAM 80® increased the shoot dry weight of plants grown with 15 and 25 ppm of bifenthrin. This study showed that mycorrhizal colonization can be helpful to overcome some of the negative effects of bifenthrin on the growth of corn.

Mycorrhizal responsiveness of Thuja, Calocedrus, Sequoia, and Sequoiadendron species of western North America

1985 ◽  
Vol 15 (6) ◽  
pp. 1049-1054 ◽  
Author(s):  
J. L. Kough ◽  
Randy Molina ◽  
R. G. Linderman
Keyword(s):  
Arbuscular Mycorrhizal Fungi ◽  
Tree Species ◽  
Mycorrhizal Fungi ◽  
Arbuscular Mycorrhizal ◽  
Mycorrhizal Colonization ◽  
Growth Enhancement ◽  
Vesicular Arbuscular Mycorrhizal Fungi ◽  
Arbuscular Mycorrhizal Colonization ◽  
Vesicular Arbuscular ◽  
Low Phosphorus

Four western conifers inoculated or not inoculated with three species of vesicular–arbuscular mycorrhizal fungi were grown in pasteurized soil and maintained at 11 or 43 ppm phosphorus. Compared with controls, vesicular–arbuscular mycorrhizal colonization increased biomass more of younger than older seedlings. In young seedlings, species with large seeds responded less to phosphate addition or vesicular–arbuscular mycorrhizal colonization than smaller seeded species. Vesicular–arbuscular mycorrhizal seedlings with low phosphorus were always larger than noninoculated low phosphorus controls and comparable in size or larger than nonmycorrhizal controls at moderate phosphorus. Vesicular–arbuscular mycorrhizal plants produced from 100 to 2000% more biomass than noninoculated plants at low phosphorus, and from equality to 500% at moderate phosphorus. Vesicular–arbuscular mycorrhizal fungal species did not differ in plant growth enhancement or root colonization at any seedling age or phosphorus fertility examined. Tree species' responsiveness ranged as follows: Thujaplicata > Sequoiasempervirens > Calocedrusdecurrens > Sequoiadendrongiganteum. Vesicular–arbuscular mycorrhizal fungi enhanced seedling uniformity and size in all the tree species.

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.

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.

Sign in / Sign up

Export Citation Format

Share Document