‘Waldsterben’, part IV (continuing series)

Summary Peroxidase and superoxide dismutase activities, and ascorbic acid content, were measured in both intercellular fluid and cell material of current and 1-year-old needles of Norway spruce saplings treated with ozone, ambient air and activated carbon-filtered air in outdoor fumigation chambers. Ethylene evolution was also compared. Plants from carbon-filtered air treatments had significantly lower enzyme activities and higher ascorbic acid content. These changes were more marked in intercellular fluid than in cell material. Significant changes were noted at ozone levels typical of ambient air quality in a typical urban area. These results suggest the need for simultaneous screening of several biochemical markers as a way of overcoming the lack of specificity of any single marker for the identification of a perturbation by a particular stress, such as ozone.Acknowledgments. This work was supported in part by Grant Number 4849-0.85 (NFP 14) from the Swiss National Fund of Scientific Research. We thank Dr. F. Cupelin and Dr. J. Cl. Landry from the Service d'Ecotoxicologie, Genève, who provided the facilities for the monitoring of ozone levels. We also thank A. Mesrobian, A. Rossier and D. Voluntaru for technical assistance. Du Pont de Nemours International is gratefully acknowledged for the gift of TEDLAR (polyvinyl fluoride film) to build up the fumigation chambers.