Mycelial development and phosphorus translocation in systems of Phanerochaete velutina interacting with resource restricted fungi

The effect of arrival of wood resources, precolonised by either Coholus versicolor, Phlebia radiata, Stereum hirsutum and Vuilleminia comedens, on mycelial systems of Phanerochaete velutina was studied in trays of non-sterile soil in the laboratory. Morphological responses and nutrient movement were quantified non-destructively using respectively image analysis and P monitoring with a scintillation probe, and subsequently destructively harvesting. The presence of a fungus occupying the new resource or state of decay of the resource arriving on an established system had major effects on deployment of biomass and on the uptake and allocation of phosphorus, the effects were specific to the species occupying the new resource. When new resources were added of constant size and decay state, massive redeployment of biomass away from regions with no new resource only occurred with three types of new resource: (1) uncolonised (2) colonised by V. comedens', and (3) to a lesser extent those colonised by S. hirsutum. P was taken up by P. velutina both in the vicinity of the inoculum and the new resource, and was translocated to the new resource from both sites of uptake, however the local supply contributed most. Bidirectional translocation also occurred. Initial P translocation to wood resources precolonised for three years by V. comedens and S. hirsutum was initially high, greater initial translocation of P occurred to younger precolonised resources of 8 weeks where a dramatic increase in P activity was apparent in systems containing the precoloniser V. comedens. Mycelial systems containing two resources, precolonised and/or uncolonised and at different states of decay had major effects on phosphorus translocation to these resources. Mycelial systems growing from different inoculum sizes effected the outcome of interactions between P. velutina and resource restricted fungi. Phosphorus translocation was also effected by inoculum to resource ratio within the system. 12 1 Lower P activity was observed in mycelial systems extending from 1cm inoculum when compared to systems extending from 4cm and 16 cm3 inoculum. An increase in inoculum to resource ratio increased the capability of cord systems of P. velutina to capture resources that were once occupied by other wood decay species. These responses are discussed in relation to mycelial foraging strategies, nutrient translocation and partitioning within mycelial cord systems