Effects of ozone on gas exchange, frost resistance, flushing and growth of different provenances of European silver fir (Abies alba Mill.)

Photosynthesis, respiration, and transpiration were studied in different Abies alba provenances during and alter ozone exposure at three different levels (0/control, 125, and 250 ppb O3, respectively). The after‐effects of ozone on frost resistance and growth rate were also analyzed. Pronounced reductions of photosynthesis and transpiration rates and an increased respiration were registered as a response to O3. Five months after exposure the winter frost resistance was significantly reduced, and growth depressions were registered during the following year. Differences in ozone sensibility and regeneration ability between provenances could be demonstrated.