Nutrient movement and mycelial reorganization in established systems of Phanerochaete velutina, following arrival of colonized wood resources.

The effect of arrival of wood resources, pre-colonized by Coriolus versicolor, Phlebia radiata, Stereum hirsutum, and Vuilleminia comedens, on mycelial systems of Phanerochaete velutina was studied in trays of nonsterile soil in the laboratory over 5 months. Morphological responses were quantified non-destructively using image analysis. In a parallel series of experiments, nutrient movement was also quantified non-destructively using (32)P monitoring with a scintillation probe and subsequently by destructively harvesting after 155 days. The presence of a fungus occupying a newly arriving resource had major effects on deployment of biomass and on the uptake and allocation of phosphorus in the established Pha. velutina system. The effects varied depending on the species occupying the new resource. Hyphal coverage was greater in the half of the system to which new resources were added. Following addition of new resources, there was massive redeployment of biomass away from regions with no new resource when the new resource was (1) uncolonized, (2) colonized by V. comedens, or (3) colonized by S. hirsutum (although to a lesser extent with the latter), but not with others. (32)P was taken up by Pha. 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. The results are discussed in relation to mycelial foraging strategies, nutrient translocation, and partitioning within mycelial cord systems.