Sulphide dioxide and the growth of Pinus sylvestris.
Seedlings and young trees of Pinus sylvestris were grown in outdoor fumigation chambers at about 5 and 150 mu SO2m-3 (5 pphm). Temperature and water vapour pressure deficit inside the chambers were higher than outside. The high level of SO2 decreased growth in two experiments, by reducing net assimilation rate, but had no significant effect in a third experiment. Leaf sulphur contents were usually raised by SO2 treatment. Stem and needle elongation were retarded by SO2 in a further experiment. The diffusive resistance of pine needles was increased following SO2 treatment, but the rate of net photosynthesis was not affected.