Wood decay, and phosphorus and fungal biomass allocation, in mycelial cord systems



Wood block inocula, of different decay states, colonized by Phanerochaete velutina (D.C.: Pers.) Parmasto and Phallus impudicus (L.) Pers., were supplied with [32P]orthophosphate 1 wk after mycelium had made contact with newly supplied sterile wood baits. Inoculum decay state affected the initial pattern of mycelial outgrowth, biomass, phosphorus uptake and subsequent decay rates of newly supplied baits. P. velutina and P. impudicus translocated up to 75 and 13 % respectively of phosphorus accumulated by the inoculum to the new supplied bait, translocation being in proportion to the decay state of the inoculum. On contact with baits, biomass was preferentially allocated to connective rather than non-connective mycelium. This was accompanied by regression of non-connective mycelium, which depended on the decay state of the inoculum. Phosphorus movement via connective cords was up to ten times higher in non-connective cords, maximal rates of 7225 nmol P cm−2 d−1 being recorded for cords from the most decayed P. velutina inocula.