Bi-directional transfer of phosphorus between red clover and perennial ryegrass via arbuscular mycorrhizal hyphal links

Abstract

Perennial ryegrass and red clover were grown in low-P soil in separate compartments within rhizoboxes. The compartments were separated by 30-µm pore nylon mesh and a buffer compartment to prevent root-to-root contact but allow hyphal penetration. Both plant species were established as donor and receiver plants. Donors were inoculated with an arbuscular mycorrhizal (AM) fungus, Glomus mosseae, forming hyphal links between donors and receivers. Two rates of P (50 and 100 mg P kg -1 ) were applied to the soil in the receiver compartments. All other compartments received 50 mg P kg -1 . In one experiment 32 P tracer was applied to the roots of the donors after 6 weeks' growth to detect P transfer from donors to receivers. In a second experiment, plants harvested 2 weeks later were examined for root AM colonisation, shoot yield and P uptake. Arbuscular mycorrhizal fungal inoculation of donor roots led to increased yield, P concentration and P uptake of receiver shoots. Shoot P concentrations were higher in non-mycorrhizal ryegrass than in non-mycorrhizal clover. The 32 P tracer study showed a lower apparent P transfer rate from ryegrass to clover than from clover to ryegrass despite a comparable amount of P transferred. Internal P requirements of the host plants may influence P transfer rates. The AM hyphae formed an important link between the plants but no appreciable net transfer of P was likely to occur.

Arbuscular mycorrhiza enhanced arsenic resistance of both white clover (Trifolium repens Linn.) and ryegrass (Lolium perenne L.) plants in an arsenic-contaminated soil

“…Thus, we chose white clover plants to compete with the demonstrated rare positively responding ryegrass plants. The white clover used here would be expected to benefit more from AM symbiosis in comparison with ryegrass (Zhu et al, 1999;Yao et al, 2003). Indeed, the present study demonstrated this effect, as indicated by the lower ryegrass/clover ratios of plant dry weights (Table 2) and P and As uptake under the inoculation treatments.…”

Plant: soil interactions in temperate multi-cropping production systems

“…Indirect N transfer via leaf litter significantly contributed to the total N uptake of the component crop, in clover leys, TBIs and forestry (Kurdali et al 1990;Dahlin and Stenberg 2010). Direct N-transfer from legumes to the component crop occurs between living plants, via mycorrhizal connections (Stern 1993;He et al 2003;Yao et al 2003;Szumigalski and Van Acker 2006). The bulk of N acquired by legumes and transferred to the component crop only becomes available after senescence (Hauggaard-Nielsen et al 2003).…”

Underground resource allocation between individual networks of mycorrhizal fungi

“…Here we assume that all 32 P transferred originated directly from the labelled soil patch only and not also from 32 P contained in the living donor plant. This is based on previous studies showing that direct interplant transfer of P via a shared mycelium is insignificant (Johansen & Jensen, 1996; Simard et al ., 2002; Yao et al ., 2003).…”