PATTERNS AND DYNAMICS OF P-32 PHOSPHATE AND LABELED 2-AMINOISOBUTYRICACID (C-14-AIB) TRANSLOCATION IN INTACT BASIDIOMYCETE MYCELIA

Following uptake of P-32-orthophosphate and C-14-aminoisobutyric acid (C-14-AIB) the patterns of distribution of the isotopes through intact basidiomycete mycelia were non-destructively mapped at regular interv als using a beta-scanner. Analysis of the results suggests that transl ocation of P-32 and C-14-AIB through mycelia of Pleurotus ostreatus an d Schizophylum commune occurred along a restricted number of clearly d efined, but macroscopically invisible, routes through the mycelium. In contrast to this, P-32 added to mycelia of Coprinus cinereus remained immobilised at the addition point. Simultaneous acropetal and basipet al translocation of P-32 and C-14-AIB was observed in different region s of colonies of P. ostreatus and S. commune. Translocation of label a round the periphery of colonies strongly suggested the existence of an astomoses around the colony margin. Both P-32 and C-14-AIB were initia lly immobilised at the addition point, from which each was subsequentl y translocated to other parts of the mycelium. The observed translocat ion of nutrients could not be explained by simple diffusion alone. The velocity of translocation and the complexity of the translocation pat tern of P-32 were greatest in mycelia of P. ostreatus, a hardwood deco mposer, followed by S. commune, a wood and litter decomposer and paras ite. Translocation through mycelia of C. cinereus, a coprophilus sapro phyte, was very slow. This study provides the first detailed descripti on of nutrient translocation through intact, entire fungal mycelia ove r time. (C) 1998 Federation of European Microbiological Societies. Pub lished by Elsevier Science B.V. All rights reserved.