This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via CrossRef Citing Articles via Google Scholar Google Scholar Articles by Campbell, W. J. Articles by Bowes, G. Search for Related Content PubMed PubMed Citation Articles by Campbell, W. J. Articles by Bowes, G. Agricola Articles by Campbell, W. J. Articles by Bowes, G.

Environmental and Stress Physiology

Effects of CO₂ Concentration on Rubisco Activity, Amount, and Photosynthesis in Soybean Leaves ¹

Agronomy Department, University of Florida, Gainesville, Florida 32611, U.S. Department of Agriculture, Agricultural Research Service, University of Florida, Gainesville, Florida 32611, Botany Department, University of Florida, Gainesville, Florida 32611

Growth at an elevated CO₂ concentration resulted in an enhanced capacity for soybean (Glycine max L. Merr. cv Bragg) leaflet photosynthesis. Plants were grown from seed in outdoor controlled-environment chambers under natural solar irradiance. Photosynthetic rates, measured during the seed filling stage, were up to 150% greater with leaflets grown at 660 compared to 330 microliters of CO₂ per liter when measured across a range of intercellular CO₂ concentrations and irradiance. Soybean plants grown at elevated CO₂ concentrations had heavier pod weights per plant, 44% heavier with 660 compared to 330 microliters of CO₂ per liter grown plants, and also greater specific leaf weights. Ribulose 1,5-bisphosphate carboxylase/oxygenase (rubisco) activity showed no response (mean activity of 96 micromoles of CO₂ per square meter per second expressed on a leaflet area basis) to short-term (1 hour) exposures to a range of CO₂ concentrations (110-880 microliters per liter), nor was a response of activity (mean activity of 1.01 micromoles of CO₂ per minute per milligram of protein) to growth CO₂ concentration (160-990 microliters per liter) observed. The amount of rubisco protein was constant, as growth CO₂ concentration was varied, and averaged 55% of the total leaflet soluble protein. Although CO₂ is required for activation of rubisco, results indicated that within the range of CO₂ concentrations used (110-990 microliters per liter), rubisco activity in soybean leaflets, in the light, was not regulated by CO₂.

¹ Florida Agricultural Experiment Station Journal Series No. 8988. This work was funded in part by U.S. Department of Energy-U.S. Department of Agriculture Interagency Agreement No. DE-AI01-81ER60001.

This article has been cited by other articles:

				F. L. Booker and E. L. Fiscus The role of ozone flux and antioxidants in the suppression of ozone injury by elevated CO2 in soybean J. Exp. Bot., August 1, 2005; 56(418): 2139 - 2151. [Abstract] [Full Text] [PDF]