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International Journal of Agronomy
Volume 2012 (2012), Article ID 309153, 6 pages
http://dx.doi.org/10.1155/2012/309153
Research Article

Responses of Metabolites in Soybean Shoot Apices to Changing Atmospheric Carbon Dioxide Concentrations

Crop Systems & Global Change Laboratory, Agricultural Research Service-USDA, Room 342, Building 001, BARC-west, 10300 Baltimore Avenue, Beltsville, MD 20705, USA

Received 12 June 2012; Accepted 11 July 2012

Academic Editor: Bernd Lennartz

Copyright © 2012 Richard Sicher. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Soybean seedlings were grown in controlled environment chambers with CO2 partial pressures of 38 (ambient) and 72 (elevated) Pa. Five or six shoot apices were harvested from individual 21- to 24-day-old plants. Metabolites were analyzed by gas chromatography and, out of 21 compounds, only sucrose and fructose increased in response to CO2 enrichment. One unidentified metabolite, Unk-21.03 decreased up to 80% in soybean apices in response to elevated CO2. Levels of Unk-21.03 decreased progressively when atmospheric CO2 partial pressures were increased from 26 to 100 Pa. Reciprocal transfer experiments showed that Unk-21.03, and sucrose in soybean apices were altered slowly over several days to changes in atmospheric CO2 partial pressures. The mass spectrum of Unk-21.03 indicated that this compound likely contained both an amino and carboxyl group and was structurally related to serine and aspartate. Our findings suggested that CO2 enrichment altered a small number of specific metabolites in soybean apices. This could be an important step in understanding how plant growth and development are affected by carbon dioxide enrichment.