Effects of a mycophagous Collembola on the symbioses betweenTrifolium subterraneumand three arbuscular mycorrhizal fungi

Abstract

SUMM.4RYWe examined the effect of the mycophagous Collembola Folsomia Candida Willem on the symbioses between Trifolium subterraneum L. and three arbuscular mycorrhizal (AM) fungi. Mycorrhizal and non-mycorrhizal plants were grown in pots with a central mesh bag -ivhich constituted a root-free soil compartment (RFSC) where the soil was labelled w-ith ^^P. This allow^ed us to study hypha] P transport as affected by the presence of CoUemhola in the soil with roots. The hyphal P transport w-as monitored by measuring the ^^P content in leaflets sampled from the latest fully developed trifoliate leaf after 3, 4, 5 and 6 w-k. Measurements on each plant after 6 wk furthermore included total contents of ^^P and ^^P, root length and length of hyphae inside the mesh bag. The presence of F. Candida reduced the average hyphal ^*P transport from the RFSC by 12 "i and the average AM hyphal length in the RFSC was reduced by 30%. The root dry weights of mycorrhizal plants were also reduced by the presence of Collembola. The reduction in total hypha] ^^P transport was not revealed by the data from the time-course study using leaflet samples, w-hich demonstrates the uncertainty of analyses of AM fungal activity based solely on measurements of leaf materials.The results from this work suggest that F. Candida grazed on roots and/or h5-phae of AM; however, shoot yields were unaffected by this grazing. In conclusion, Collembola seemed to have little effect on the functioning of AM fungi.

Decomposers (Lumbricidae, Collembola) Affect Plant Performance in Model Grasslands of Different Diversity

“…Reduced root biomass in presence of collembolans has been observed in a number of studies (Larsen and Jakobsen 1996, Bardgett and Chan 1999, Scheu et al 1999, Kreuzer et al 2004) and has been ascribed to a collembolan-mediated increase in plant nutrient uptake (Lussenhop and BassiriRad 2005). Compared to roots earthworms disproportionately increased shoot biomass, resulting in an increased shoot-to-root ratio.…”

Interactions between arbuscular mycorrhizal fungi and the hemiparasitic angiosperm Rhinanthus minor during co‐infection of a host

“…However, given that in grasses it has been shown that the AM symbiosis can afford increased resistance to fungal pathogens (Newsham et al, 1995) the observed reduction in AM colonization might carry a cost which could not be detected in the current study. Indeed, Larsen & Jakobsen (1996) comment that whilst they found no effect of Collembola feeding in AM functioning, other studies had observed such a response and that impacts on the host might therefore, be contextually dependent. Further research, involving field trials would be desirable in order to clarify this issue.…”

Microbial-faunal interactions in the rhizosphere and effects on plant growth

“…However, fungal feeding microarthropods also detrimentally affect the hyphal network by severing hyphal branches at their bases even when offered a greater range of fungi as food sources [75]. The infection rate by arbuscular mycorrhiza and therefore plant growth was found to decrease with increasing collembolan density in pot experiments [44,58,81,85,88,129]. Microarthropod densities in laboratory experiments are often unnaturally high and moderate arthropod grazing which may be closer to what occurs in the field, has been shown to stimulate mycorrhizal growth [40,44,85,90].…”