Arabidopsis thaliana (L.) Heynh. was exposed to
various concentrations of SO2 during almost the entire
life cycle. No negative effects of SO2 on shoot biomass
production were observed. There was a linear relation between the
deposition of SO2 and the atmospheric SO2
concentration. Sulphur accumulated substantially in the shoots upon
SO2 exposure. SO2 was either oxidized to
sulphate or converted into extra organic sulphur compounds in a
sulphate to organic sulphur ratio of 3[ratio ]1, independently of the
atmospheric SO2 concentration. Exposure to SO2
resulted in an increase in water soluble non-protein sulphydryl
content and a slight increase in the amount of glucosinolates, but
both of these play a minor role as sinks for the excess sulphur. The
ratio of total nitrogen to total sulphur decreased upon
SO2 exposure as a result of the increased sulphate
content. The organic nitrogen to organic sulphur ratio did not change
upon SO2 exposure, indicating no changes in the
composition of sulphur-containing compounds.