SULFUR-DIOXIDE EFFECTS ON FUNGI GROWING ON LEAF-LITTER AND AGAR MEDIA

Respiration of four decomposer fungi (Mycena galopus (Pers.) Kummer, A ureobasidium pullulans (de Bary) Arnaud, Phoma exigua Desm. and Clados porium cladosporioides (Fres.) de Vries) growing on four species of le af litter (Pinus sylvestris L., Picea sitchensis (Bongard) Carriere, F raxinus excelsior L. and Corylus avellana L.) was inhibited by dry-dep osited SO2 in a laboratory experiment. Mycelial extension of the four fungi growing on four different agar media was inhibited by SO2 fumiga tion (40 nl l(-1)) in the laboratory, and media containing carbohydrat es decreased the inhibitory effect of SO2 fumigation. Fumigation cause d a statistically significant reduction in the mycelial extension of a ll species tested on tap-water agar. These experiments demonstrate tha t decomposition of leaf litter is inhibited by environmentally realist ic concentrations of SO2 and that the effect is exerted via inhibition of saprotrophic fungi.