JXB Advance Access originally published online on June 23, 2006
Journal of Experimental Botany 2006 57(10):2267-2275; doi:10.1093/jxb/erj199
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RESEARCH PAPER |
Anticipated yield loss in field-grown soybean under elevated ozone can be avoided at the expense of leaf growth during early reproductive growth stages in favourable environmental conditions
1ICG-III (Phytosphere), Research Center Juelich, D-52425 Juelich, Germany
2USDA-Agricultural Research Service, Photosynthesis Research, and Soybean/Maize Germplasm, Pathology, and Genetics Research Units, University of Illinois, Urbana-Champaign, Urbana, IL 61801, USA
3Department of Plant Biology, University of Illinois, Urbana-Champaign, Urbana, IL 61801, USA
4Department of Crop Sciences, University of Illinois, Urbana-Champaign, Urbana, IL 61801, USA
*To whom correspondence should be addressed. E-mail: a.walter{at}fz-juelich.de
Ozone is a powerful oxidizing agent which is responsible for more damage to vegetation than any other air pollutant. In this study, leaf growth, photosynthesis, and carbohydrate content were analysed during the seed-filling growth stage of field-grown soybeans exposed to ambient air and 1.2 times ambient ozone concentration using a Free Air Concentration Enrichment (FACE) facility. By contrast to predictions based on controlled-environment and open-top chamber studies, final yield did not differ between treatments, although the cultivar used here was sensitive to ozone damage: growth and carbohydrate content of upper canopy leaves was reduced during the seed-filling stage in which an ozone-induced decrease of photosynthesis was present. However, 2004 was an ideal growing season in central Illinois and the cumulative ozone indices were lower than in previous years. Still, the results indicate that the anticipated yield loss under ozone concentrations was avoided at the expense of leaf growth, as reserves were diverted from vegetative to reproductive organs.
Key words: Carbohydrates, global atmospheric change, Glycine max, leaf growth, photosynthesis, stomatal density