Sequential encounter of wood resources by mycelial cords of Phanerochaete velutina: effect on growth patterns and phosphorus allocation



The effect of sequential encounter with wood resources (1 cm3 and 2 cm3‘baits’ in various combinations) by mycelial cords of Phanerochaete velutina (DC.: Pers.) Parmasto growing from 1 cm3 wood inocula was investigated in model soil systems in the laboratory. Encountering large wood baits (8 cm3), either next to the inoculum or after encounter of another bait, resulted in cessation of mycelial extension and regression of mycelium from the inoculum and small baits. Small wood baits had no effect on mycelial extension rates, even when encountered in rapid succession. All systems maintained a general polarity when growing out from a bait, but later often curved around the bait, extending over soil which had previously been explored. Allocation of 32P (taken up by the inoculum) between the three resource units (inoculum and two sequentially encountered baits) was investigated; significantly (P≤ 0.05) more 32P was allocated to the large wood baits (whether encountered first or second) than to the other bait; but the inoculum was usually allocated most. Wood inocula decayed more rapidly than baits. The significance of the results is discussed in relation to foraging.