In conclusion, O3 fumigation induced inhibition of photosynthesis
by enhanced stomatal closure, decreased capacity
of QA re-oxidation by inhibition of Calvin cycle (decreased
in CO2 fixation) through an increasing heat dissipation process.
Ozone increased SOD and APX activities, although
these mechanisms do not seem to be completely sufficient to
protect plants against oxidative stress, as shown by the increased
lipid peroxidation, decreased AsA pool and minor
photosynthetic rates.