How does elevated ozone impact soybean? A meta‐analysis of photosynthesis, growth and yield

• Published in: Plant, cell and environment Vol. 26; no. 8; pp. 1317 - 1328
• Main Authors: MORGAN, P. B., AINSWORTH, E.A., LONG, S. P.
• Format: Journal Article
• Language: English
• Published: Oxford, UK Blackwell Science Ltd 01.08.2003; Blackwell; Wiley Subscription Services, Inc
• Subjects: Animal, plant and microbial ecology; Applied ecology; atmospheric change; atmospheric pollution; Biological and medical sciences; biomass; carbon dioxide; crop yield; drought; dry matter accumulation; Ecotoxicology, biological effects of pollution; Effects of pollution and side effects of pesticides on plants and fungi; elevated atmospheric gases; elevated CO2; filling period; Fundamental and applied biological sciences. Psychology; global change; Glycine max; harvest index; Non agrochemicals pollutants; ozone; Photosynthesis; Phytopathology. Animal pests. Plant and forest protection; plant response; plant stress; Pollution effects and side effects of agrochemicals on crop plants and forest trees. Other anthropogenic factors; Pollution effects. Side effects of agrochemicals; reproductive output; Soybeans; stomatal conductance; UV‐B; vegetative growth; biomass; atmospheric change; O3; Growth; Ozone; reproductive output; Glycine max; UV-B; atmospheric pollution; Leguminosae; Seed yield; drought; elevated CO2; Dicotyledones; global change; Angiospermae; harvest index; Air pollution; Spermatophyta; Photosynthesis
• ISSN: 0140-7791; 1365-3040
• DOI: 10.1046/j.0016-8025.2003.01056.x

ABSTRACT Surface ozone concentrations ([O3]) during the growing season in much of the northern temperate zone reach mean peak daily concentrations of 60 p.p.b. Concentrations are predicted to continue to rise over much of the globe during the next 50 years. Although these low levels of ozone may not induce visible symptoms on most vegetation, they can result in substantial losses of production and reproductive output. Establishing the vulnerability of vegetation to rising background ozone is complicated by marked differences in findings between individual studies. Ozone effects are influenced by exposure dynamics, nutrient and moisture conditions, and the species and cultivars that are investigated. Meta‐analytic techniques provide an objective means to quantitatively summarize treatment responses. Soybean has been the subject of many studies of ozone effects. It is both the most widely planted dicotyledonous crop and a model for other C3 annual plants. Meta‐analytic techniques were used to quantitatively summarize the response of soybean to an average, chronic ozone exposure of 70 p.p.b., from 53 peer‐reviewed studies. At maturity, the average shoot biomass was decreased 34% and seed yield was 24% lower. Even in studies where [O3] was < 60 p.p.b., there was a significant decrease in biomass and seed production. At low [O3], decreased production corresponded to a decrease in leaf photosynthesis, but in higher [O3] the larger loss in production was associated with decreases in both leaf photosynthesis and leaf area. The impact of ozone increased with developmental stage, with little effect on vegetative growth and the greatest effect evident at completion of seed filling. Other stress treatments, including UV‐B and drought, did not alter the ozone response. Elevated carbon dioxide significantly decreased ozone‐induced losses, which may be explained by a significant decrease in stomatal conductance.