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Öğe Secondary effects of SO2 pollution on leachate chemistry and decay of scots pine and mixed angiospermous leaf litters(Elsevier Ltd, 1996) Dursun, S.; Boddy, Lynne; Frankland, Juliet C.; Ineson, P.The secondary effects of SO2 fumigation on CO4 evolution from leaf litter of Scots pine (Pinus sylvestris L.) and mixed broad-leaved species [Quercus petraca mattuschka (Liebl.), Fraxinus excelsior L., Betula pubescens Ehrh., Betula pendula Roth., Acer pseudoplatanus L. and Corylus avellana L.] were investigated. Respiration of Phoma exigua Desm. inoculated onto both types of previously fumigated (48 nl l-1), sterile litter was higher than controls (< 10 nl l-1). Much higher rates of CO4 evolution were measured from control litters than from fumigated litters after 2 weeks; the differences decreased but continued until the end of the 12-wk incubation period. Sulphate concentrations in the leachate solution from fumigated litters remained significantly higher until the end of experiment. In addition, the pH of the leachate solution was lowered by SO2 fumigation. At the start of the experiment, the NH4/+ concentration from pre-fumigated and control litters was similar, but release from the control litter was slightly greater than from pre-fumigated litter, according with measurements of CO2 evolution from the litters. The experiments indicated that environmentally-realistic concentrations of SO2 over a long period could affect leachate chemistry and this might affect the decomposition rate of leaf litters. The Scot pine litter was more affected than mixed angiospermous litter.Öğe Sulphite and pH effects on CO2 evolution by fungi growing on decomposing coniferous needles(Blackwell Publishing Ltd., 1996) Dursun, S.; Frankland, Juliet C.; Boddy, Lynne; Ineson, P.The relative sensitivities of Mycena galopus (Pers.) Kummer, Phoma exigua (Desm.), Cladosporium cladosporioides (Fres.) de Vries and Aureobasidium pullulons (de Bary) Arnaud to low concentrations (12·5-100·0 ?M) of sulphite (SO32-) when growing on decomposing needles of Picea sitchensis (Bongard) Carrière (Sitka spruce) and Pinus sylvestris L. (Scots pine) were assessed. Carbon dioxide evolution from the decomposing needles was strongly inhibited by SO32- at pH 3·0-4·5. P. exigua was the most sensitive of the species tested in the mycelial state, and C. cladosporioides was the most sensitive species tested as spores. Mycelium was consistently less sensitive than spores. The inhibitory effect of SO32- on CO2 evolution was increased by increasing the SO32- concentration or decreasing the pH. The concentrations shown to exert toxicity were similar to those which have been measured in rainfall in the UK, and the results provide evidence that SO32- can be toxic to litter fungi at environmentally realistic concentrations.Öğe Sulphur dioxide effects on fungi growing on leaf litter and agar media(Blackwell Publishing Ltd., 1996) Dursun, S.; Ineson, P.; Frankland, Juliet C.; Boddy, LynneRespiration of four decomposer fungi (Mycena galopus (Pers.) Kummer, Aureobasidium pullulans (de Bary) Arnaud, Phoma exigua Desm. and Cladosporium cladosporioides (Fres.) de Vries) growing on four species of leaf litter (Pinus sylvestris L., Picea sitchensis (Bongard) Carrière, Fraxinus excelsior L. and Corylus avellana L.) was inhibited by dry-deposited SO2 in a laboratory experiment. Mycelial extension of the four fungi growing on four different agar media was inhibited by SO2 fumigation (40 nl 1-1) in the laboratory, and media containing carbohydrates decreased the inhibitory effect of SO2 fumigation. Fumigation caused a statistically significant reduction in the mycelial extension of all species tested on tap-water agar. These experiments demonstrate that decomposition of leaf litter is inhibited by environmentally realistic concentrations of SO2 and that the effect is exerted via inhibition of saprotrophic fungi.
