DERIVING CRITICAL LEVELS FOR OZONE EFFECTS ON PEACH-TREES (PRUNUS-PERSICA (L) BATSCH) GROWN IN OPEN-TOP CHAMBERS IN CENTRAL ITALY

The definition of critical levels (CL) of pollutants, i.e. the level o f a gaseous pollutant above which negative effects may occur, is an im portant element to predict potential impacts on plants, and to design effect-oriented abatement strategies under the Convention on Long-Rang e Transboundary Air Pollution (United Nations Economic Commission for Europe, UNECE). Data from a recent fumigation experiment in which peac h trees [Prunus persica (L.) Batsch] grown in open-top chambers in Cen tral Italy were exposed to a range of realistic ozone levels, were ana lysed to derive exposure-response relationships for different exposure indices, such as the accumulated exposure over a threshold of 40 nL L (-1), AOT40. From the linear regression equations, the CL correspondin g to a 10% change for ozone-responsive plant parameters was calculated . The results suggest that economically important traits of fruit tree s in the Mediterranean area may not be protected by the current CL set for agricultural crops.