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Abstract Tropospheric ozone ( O 3 ) is a harmful air pollutant that can negatively impact plant growth and development. Current O 3 concentrations ( O 3 ) decrease forest productivity and crop yields and future O 3 will likely increase if current emission rates continue. However, the specific effects of elevated O 3 on reproductive development, a critical stage in the plant's lifecycle, have not been quantitatively reviewed. Data from 128 peer‐reviewed articles published from 1968 to 2010 describing the effects of O 3 on reproductive growth and development were analysed using meta‐analytic techniques. Studies were categorized based on experimental conditions, photosynthetic type, lifecycle, growth habit and flowering class. Current ambient O 3 significantly decreased seed number (−16%), fruit number (−9%) and fruit weight (−22%) compared to charcoal‐filtered air. In addition, pollen germination and tube growth were decreased by elevated O 3 compared to charcoal‐filtered air. Relative to ambient air, fumigation with O 3 between 70 and 100 ppb decreased yield by 27% and individual seed weight by 18%. Reproductive development of both C 3 and C 4 plants was sensitive to elevated O 3 , and lifecycle, flowering class and reproductive growth habit did not significantly affect a plant's response to elevated O 3 for many components of reproductive development. However, elevated O 3 decreased fruit weight and fruit number significantly in indeterminate plants, and had no effect on these parameters in determinate plants. While gaps in knowledge remain about the effects of O 3 on plants with different growth habits, reproductive strategies and photosynthetic types, the evidence strongly suggests that detrimental effects of O 3 on reproductive growth and development are compromising current crop yields and the fitness of native plant species.
Leisner et al. (Thu,) studied this question.