Diversity of Arbuscular Mycorrhizal Fungi and Ecosystem Functioning

Hart, Miranda M.; Klironomos, John N.

doi:10.1007/978-3-540-38364-2_9

Cited by 71 publications

(68 citation statements)

References 52 publications

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“…This suggests that the investigated fungi had similar physiological effects on the plants, even though root colonization levels of sunflower and some of the investigated weed species differed significantly among treatments with different AMF taxa. Variations in growth effects by different AMF taxa appear to be largest at the genus level, not at the species or isolate level (Hart and Klironomos 2002). Hence, this indicates that it is more likely to find complementary effects of AMF diversity when different AMF genera (with different strategies) are present (de la Providencia et al 2005).…”

Section: Discussionmentioning

confidence: 99%

Mycorrhizal fungi suppress aggressive agricultural weeds

et al. 2009

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Plant growth responses to arbuscular mycorrhizal fungi (AMF) are highly variable, ranging from mutualism in a wide range of plants, to antagonism in some non-mycorrhizal plant species and plants characteristic of disturbed environments. Many agricultural weeds are non mycorrhizal or originate from ruderal environments where AMF are rare or absent. This led us to hypothesize that AMF may suppress weed growth, a mycorrhizal attribute which has hardly been considered. We investigated the impact of AMF and AMF diversity (three versus one AMF taxon) on weed growth in experimental microcosms where a crop (sunflower) was grown together with six widespread weed species. The presence of AMF reduced total weed biomass with 47% in microcosms where weeds were grown together with sunflower and with 25% in microcosms where weeds were grown alone. The biomass of two out of six weed species was significantly reduced by AMF (−66% & −59%) while the biomass of the four remaining weed species was only slightly reduced (−20% to −37%). Sunflower productivity was not influenced by AMF or AMF diversity. However, sunflower benefitted from AMF via enhanced phosphorus nutrition. The results indicate that the stimulation of arbuscular mycorrhizal fungi in agro-ecosystems may suppress some aggressive weeds.

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Section: Discussionmentioning

confidence: 99%

Mycorrhizal fungi suppress aggressive agricultural weeds

et al. 2009

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“…It is also highly likely that the species composition of fungi in the root system changes seasonally, as molecular studies have shown that this happens in other plants (Helgason et al 1999). Furthermore, mycorrhizal species show spatial heterogeneity in their distributions (Hart & Klironomos 2002). Given that different AM species or combinations can have different effects on plant growth (Sanders 2002), it is likely that they will also have different effects on size inequality.…”

Section: Discussionmentioning

confidence: 99%

Interactions between arbuscular mycorrhizal fungi and intraspecific competition affect size, and size inequality, of Plantago lanceolata L.

Ayres¹,

Gange

Aplin

2006

Journal of Ecology

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Summary1 Intraspecific competition causes decreases in plant size and increases in size inequality. Arbuscular mycorrhizas usually increase the size and inequality of non-competing plants, but mycorrhizal effects often disappear when plants begin competing. We hypothesized that mycorrhizal effects on size inequality would be determined by the experimental conditions, and conducted simultaneous field and glasshouse experiments to investigate how AM fungi and intraspecific competition determine size inequality in Plantago lanceolata . 2 As predicted, plant size was reduced when plants were competing, in both field and controlled conditions. However, size inequality was unexpectedly reduced by competition. Plants may have competed in a symmetric fashion, probably for nutrients, rather than the more common situation, in which plant competition is strongly asymmetric. 3 Mycorrhizas had no effect on plant size or size inequality in competing plants in either field or controlled conditions, possibly because competition for nutrients was intense and negated any benefit the fungi could provide. 4 The effects of mycorrhizas on non-competing plants were also unexpected. In field-grown plants, AM fungi increased plant size, but decreased size inequality: mycorrhizal plants were more even in size, with few very small individuals. In glasshouse conditions, mycorrhizal colonization was extremely high, and was generally antagonistic, causing a reduction in plant size. Here, however, mycorrhizas caused an increase in size inequality, supporting our original hypothesis. This was because most plants were heavily colonized and small, but a few had low levels of colonization and grew relatively large. 5 This study has important implications for understanding the forces that structure plant communities. AM fungi can have a variety of effects on size inequality and thus potentially important influences on long-term plant population dynamics, by affecting the genetic contribution of individuals to the next generation. However, these effects differ, depending on whether plants are competing or not, the degree of mycorrhizal colonization and the responsiveness of the plant to different colonization densities.

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“…Mycorrhizal fungi provide many important ecosystem functions and services at multiple scales: they influence resource acquisition in individual plants, productivity and diversity in plant communities, above-and belowground herbivore interactions, nutrient cycling, soil stability, and carbon sequestration in soils (Newsham et al 1995;van der Heijden et al 1998;Gehring and Whitham 2002;Miller and Jastrow 2000;Rillig 2004a;Johnson et al 2006). Preserving the functions and services that AM fungi provide in ecosystems requires a better understanding of Glomeromycotan biogeography because individual species and isolates function differently (Hart and Klironomos 2002;Hart and Reader 2002). Different taxa have been shown to provide different growth benefits to plants (Sanders and Fitter 1992;Klironomos 2003).…”

Section: Soil Conservation Requires a Better Understanding Of Am Fungmentioning

confidence: 99%