|Ainsworth, Elizabeth - Lisa|
Submitted to: Global Change Biology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/5/2011
Publication Date: 2/1/2012
Citation: Leisner, C.P., Ainsworth, E.A. 2012. Quantifying the effects of ozone on plant reproductive growth and development. Global Change Biology. 18(2):606-616. Interpretive Summary: Ground-level ozone is one of the most harmful pollutants for crops. While the detrimental effects of ozone on plant photosynthesis and vegetative growth are well-documented, there is less certainty about the effects of elevated ozone on reproductive development, such as the initiation of flowers and seeds. This meta-analysis quantitatively assessed plant reproductive responses to elevated ozone. We found the elevated ozone decreases pollen germination, pollen tube growth, flower mass, fruit mass, seed mass and crop yields. Plants with the C4 photosynthetic pathway (such as maize) were just as sensitive to ozone as plants with the C3 photosynthetic pathway. These results have important implications for future crop productivity as well as the fitness and fecundity of plants in natural ecosystems.
Technical Abstract: Tropospheric ozone is a harmful air pollutant that can negatively impact plant growth and development. Current ozone concentrations negatively impact forest productivity and crop yields, and future ozone concentrations will increase if current emission rates continue. However, the specific effects of elevated ozone on reproductive development, a critical stage in the plant’s lifecycle, have not been quantitatively reviewed. Data from 131 peer-reviewed articles describing the effects of ozone on reproductive growth and development were analyzed using meta-analytic techniques. Studies were categorized based on experimental conditions, photosynthetic type, growth habit, and flowering class. Current ambient ozone significantly decreased seed number, fruit number and fruit weight compared to charcoal-filtered air. Elevated ozone decreased pollen germination and tube growth as well as flower and fruit biomass. Reproductive development of both C3 and C4 plants was sensitive to elevated ozone, and elevated carbon dioxide concentrations ameliorated many of the negative consequences of ozone on reproductive parameters. While gaps in knowledge remain about the effects of O3 on plants with different growth habits and reproductive strategies, the detrimental effects of elevated ozone on reproductive growth and development may compromise future crop yields and the fitness of native plant species.