Description:
<jats:title><jats:sc>summary</jats:sc></jats:title><jats:p>Needles from young and mature Scots pine trees (<jats:italic>Pinus sylvestirs</jats:italic>) were collected at three field sites in eastern Germany, i.e. Menz, Taura, and Gossa, which differed in SO<jats:sub>2</jats:sub>pollution. Current and previous year's needles from the polluted sites Taura and Gossa (yearly mean af SO<jats:sub>2</jats:sub>: 26 ppb) contained approximately 100‐120 μmol sulphate g<jats:sup>−1</jats:sup>d. wt, whereas needles tram the unpolluted site, Menz (yearly mean of SO<jats:sub>2</jats:sub>: 3 ppb) contained 30‐65 μmol sulphate g<jats:sup>−1</jats:sup>d. wt. The apoplastic sulphate content was in the order of o.3‐1% of total sulphate and corresponded to concentrations of 0.6‐1.2 mM in needles from Mtnz and to 1.5–2 mn in needles from Gossa. In needles from the polluted sites the contents of glutathione, cysteine, γ glutamyleysteine, and soluble protein were higher than in needles from Menz. Despite the clear increases in sulphur‐containing compounds, pigment content and activities of superoxide dismutase, total peroxidase and apoplastic peroxidase (on the basis of d. wt) were not significantly different. When enzymatic activities were related to protein, lowest activities were found in needles from the site with the highest SO<jats:sub>2</jats:sub>‐pollution. The results show that it is not possible to use the activities of peroxidases or superoxide dismutases as biomarkers for SO<jats:sub>2</jats:sub>‐mediated stress in pine needles. It remains open whether the needles from the polluted sites suffered from greater oxidative stress than the needles from the less polluted site.</jats:p>