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United States Department of Agriculture

Agricultural Research Service

Title: The Role of Ozone Flux and Antioxidants in the Suppression of Ozone Injury by Elevated Carbon Dioxide in Soybean

Authors
item Booker, Fitzgerald
item Fiscus, Edwin

Submitted to: Journal of Experimental Botany
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: December 20, 2004
Publication Date: July 14, 2005
Citation: Booker, F.L., Fiscus, E.L. 2005. The role of ozone flux and antioxidants in the suppression of ozone injury by elevated carbon dioxide in soybean. Journal of Experimental Botany. 56:2139-2151.

Interpretive Summary: As atmospheric carbon dioxide concentration continues to rise from pre-industrial levels, it has in the past 50 years been accompanied by significant increases in pollutant ozone. A critical issue is how these changes will affect agricultural production. A three-year experiment with soybean in open-top field chambers showed that twice-ambient concentrations of carbon dioxide protected plants against the deleterious effects of ozone on plant growth and yield. Experimental manipulations of ozone concentration and measurements of plant ozone uptake indicated that protection against ozone could be accounted for by reduced ozone uptake as well additional as yet unknown mechanisms, possibly by increased availability of carbohydrates with elevated carbon dioxide. Increased carbohydrates might have been used for growth, detoxification and repair processes that counteracted the ozone effects. This research provides the detailed understanding of crop responses needed to support predictive modeling assessments of the impact of future climatic conditions. Ultimately this information should benefit ecosystems managers and plant breeders who may be able to optimize the effects of global climate change on agricultural productivity.

Technical Abstract: With increasing atmospheric concentrations of trace gases such as carbon dioxide and ozone, agricultural crops are being exposed to environmental conditions that affect productivity. While elevated concentrations of atmospheric carbon dioxide typically increase crop biomass and yield, ambient levels of ozone in many urbanized regions tend to suppress crop growth and yield. However, elevated carbon dioxide often ameliorates deleterious ozone effects, but the physiological mechanisms responsible for this effect are uncertain. In a three-year experiment, pot-grown soybean (cv. Essex) was exposed from emergence to maturity to charcoal-filtered air (CF) or CF air plus a range of ozone concentrations in combination with ambient or twice ambient carbon dioxide in open-top field chambers. In general, elevated carbon dioxide counteracted the suppressive effects of ozone on growth and yield. Experimental manipulations of ozone concentration and measurements of plant ozone uptake indicated that protection against ozone injury could be accounted for by reduced ozone uptake as well as additional as yet unknown mechanisms, possibly by increased availability of carbohydrates with elevated carbon dioxide. Increased carbohydrates might have been used for growth, detoxification and repair processes that counteracted the ozone effects. This research provides the detailed understanding of crop responses needed to support predictive modeling assessments of the impact of future climatic conditions. Ultimately this information should benefit ecosystems managers and plant breeders who may be able to optimize the effects of global climate change on agricultural productivity.

Last Modified: 4/19/2014
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