EFFECT OF TEMPERATURE ON WOOD DECAY AND TRANSLOCATION OF SOIL-DERIVED PHOSPHORUS IN MYCELIAL CORD SYSTEMS

Uptake of P-32 phosphorus from soil was investigated at 5-25 degrees C in mycelial cord systems of Phanerochaete velutina (D.C.: Pers.), Hypholoma fasciculare (Huds.: Fr.) Kummer and Phallus impudicus (L.) Pers. which extended from 2 cm(3) beech (Fagus sylvatica) inocula, and which had initially developed at either 10 or 25 degrees C. Uptake of phosphorus from soil was opportunistic, being unaffected by the presence of additional wood resource units in mycelial cord systems. The magnitude of phosphorus uptake was dependent on species, temperature during uptake and the temperature at which cord systems developed. Phosphorus translocation to newly colonized baits, determined non-destructively, was characterized by an initial rapid flux to a plateau in all three species. initial rates of phosphorus translocation (up to 18.46 nmol P d(-1)) generally increased with temperature whilst total translocation was species and temperature dependent. There was evidence that both P. velutina and H. fasciculare displayed temperature acclimation, since phosphorus uptake and translocation at lower temperatures was greater in cord systems which had developed initially at 10 degrees compared with 25 degrees C. Mycelial extension and wood decay rates also varied with species, initial development temperature and subsequent incubation temperature, but did not correlate with the temperature profiles of phosphorus uptake and translocation. Results are discussed in relation to nutrient acquisition, conservation and cycling in basidiomycete mycelial cord systems.