Variable responses of old-field perennials to arbuscular mycorrhizal fungi and phosphorus source

Abstract

If arbuscular mycorrhizal fungi (AMF) promote phosphorus partitioning of plant hosts, they could provide one mechanism for the maintenance of plant community diversity. We investigated whether AMF improved the ability of old field perennials to grow on a range of phosphorus sources and whether AMF facilitated differential performance of plant species on different phosphorus sources (phosphorus niche partitioning). We manipulated form of phosphorus (control versus different inorganic and organic sources) and AM fungal species (control versus four individual AMF species or an AMF community) for five old field perennials grown in a greenhouse in individual culture. Based on biomass after four months of growth, we found no evidence for phosphorus niche partitioning. Rather, we found that effects of AMF varied from parasitic to mutualistic depending on plant species, AMF species, and phosphorus source (significant Plant x Fungus x Phosphorus interaction). Our results suggest that the degree of AMF benefit to a plant host depends not only on AMF species, plant species, and soil phosphorus availability (as has also been found in other work), but can also depend on the form of soil phosphorus. Thus, the position of any AMF species along the mutualism to parasitism continuum may be a complex function of local conditions, and this has implications for understanding plant competitive balance in the field.

Aboveground environment type, soil nutrient content and arbuscular mycorrhizal fungi explain establishment success of Centaurea jacea on ex-arable land and in late-successional grasslands

“…The latter advantage would result from the greater benefit derived from AM fungi by later-successional species http://doc.rero.ch than by early-successional species (Janos 1980). The level of AM fungal colonization of plant roots and its effect on plant growth may vary depending on the composition and abundance of the AM fungal species (Van der Heijden et al 1998) and the available nutrients (Reynolds et al 2006). The significant correlations between abiotic soil characteristics, such as water content, N:P ratio, P and K concentrations, and the fraction of colonized root length containing arbuscules across aboveground and belowground environment types confirm the results of previous studies (Sanders and Sheikh 1983;Smith and Read 1997;Blanke et al 2005).…”

Sanctions, Cooperation, and the Stability of Plant-Rhizosphere Mutualisms

“…Coexisting plant species in a certain space harbor distinct AMF communities (Vandenkoornhuyse et al 2003). In some instances, host-fungal combinations have specific functional advantages, such as protection against herbivory (Bennett & Bever 2007), increased P uptake (Helgason et al 2002), and uptake of different P sources (Reynolds et al 2006). However, mycorrhizal communities hosted by plants can also exhibit maladaptive associations, with particular fungal strains proliferating in number, even though these strains may be less beneficial than others to their host plant (Bever 2002).…”

Growth response of maize plants (Zea mays L.) to wheat and lentil pre-cropping and to indigenous mycorrhizae in field soil

“…The research results of Reynolds et al (2006) suggested that the degree of AMF benefit to a plant host depends not only on AMF species, but also on the plant species and on the soil phosphorus availability. There is a general perception that P uptake by plants occurs as a direct consequence of uptake from the soil by root cells.…”