How does temperature affect forest 'fungus breath'? Diurnal non-exponential temperature-respiration relationship, and possible longer-term acclimation in fungal sporocarps

摘要

Fungal respiration contributes substantially to ecosystem respiration, yet its field temperature response is poorly characterized. I hypothesized that at diurnal time scales, temperature-respiration relationships would be better described by unimodal than exponential models, and at longer time scales both Qio and mass-specific respiration at 10 degrees C (Rms(10)) would show signs of acclimation. I measured respiration on intact sporocarps over the course of several days, and modeled temperature-respiration relationships using exponential and unimodal Gaussian functions. Unimodal models provided a better fit than exponential models. Rms(10) and Q(10) also declined with increasing temperature, consistent with longer term temperature acclimation. There was some evidence of diurnal hysteresis. When exponential models were appropriate, Q(10) values averaged similar to 3.5, and Rms(10) averaged 0.02 mu mol CO2 g(-1) sec(-1). The observed high mass-specific respiration rates, peaked temperature responses, decline in Rms(10) and Q(10) with increasing temperature, and hysteresis could contribute to observed non-exponential and hysteretic patterns in soil and ecosystem respiration. Published by Elsevier Ltd.