Does elevated ozone have differing effects in flowering and deblossomed strawberry?

Fruiting and deblossomed plants of strawberry (Fragaria x ananassa) were ex posed to 92 ppb ozone or filtered air in open-top chambers for 69 d. Flower and fruit production, relative growth rate of leaf area, leaf gas exchange and plant biomass were investigated. Ozone caused an initial acceleration in inflorescence production, which was followed by a reduction in infloresc ence production, fruit set, and, later, individual fruit weight, although t otal fruit yield was not affected before the end of the fumigation period. Ozone accelerated leaf senescence and had a greater negative effect on the rate of photosynthesis in older than in younger leaves in fruiting and debl ossomed plants, but the response of net photosynthesis to ozone did not dif fer between the two groups of plants. Relative growth rate of leaf area was the first parameter to be reduced by ozone fumigation, with the effect bei ng significant in fruiting, but not in deblossomed, plants. Final above-gro und biomass was also significantly decreased by ozone in fruiting plants, b ut not in deblossomed plants. Root and crown biomass were not significantly affected by ozone fumigation in either fruiting or deblossomed plants.