Influence of arbuscular mycorrhizal fungi, inoculum level and posphorus placement on growth and posphorus uptake of Phyllanthus calycinus under jarrah forest soil

Phosphorus uptake and biomass production mayvary between arbuscular mycorrhizas (AM) species ofcontrasting life cycles and their modes of interaction withhost plants. This research investigated differences amongthree AM fungi from different genera isolated from thejarrah forest with respect to their colonisation, biomassproduction and P uptake over time. The understorey plantPhyllanthus calycinus, has been shown to be extensivelymycorrhizal. We examined differences in the capacity offungi associated with this plant to access a P point sourcefrom increasing distances from the root. The methodologysimulated “pockets” of P in forest soil. Phosphorus sourcesin root-exclusion mesh bags were inserted 2, 4 and 6 cmfrom plant roots restrained in separate mesh bags. Acaulosporalaevis colonised plants to the greatest extent,producing higher plant biomass and P uptake compared tothe other two fungi. Plant biomass and P uptake wereenhanced where P sources were closest to the root, asexpected, but there were differences among fungi inresponse to level of inoculum used for each fungus. Thecapacity of individual AM fungi to access a point source ofP at different distances varied in a highly mycorrhizalnative forest understorey plant in parallel with plant growthand P uptake.