ANALYSIS OF VERTICAL OZONE AND NITROGEN-OXIDES PROFILES IN A PRUNUS-CERASIFERA CANOPY

An automatic system was installed for continuous analyses of ozone, su lphur dioxide, nitrogen monoxide and nitrogen dioxide in an experiment al orchard with a canopy of Prunus cerasifera plants in summer 1993. A ir samples from three elevations (0.8 m, 1.6 m and 3 m above ground) w ere sequentially analyzed. Ozone concentrations above the canopy were usually higher than within the canopy; their relationships with stomat al resistance have been investigated. Sulphur dioxide levels were negl igible. Nitrogen oxides showed a complex profile, with no particular t rend, likely due to a reciprocal exchange between the atmosphere and t he ground surface.