Does a Low Nitrogen Supply Necessarily Lead to Acclimation of Photosynthesis to Elevated CO₂?¹

Peter K. Farage, Ian F. McKee, and Steve P. Long^*

Department of Biological Sciences, John Tabor Laboratories, University of Essex, Wivenhoe Park, Colchester, Essex CO4 3SQ, United Kingdom

Long-term exposure of plants to elevated partial pressures of CO₂ (pCO₂) often depresses photosynthetic capacity. The mechanistic basis for this photosynthetic acclimation may involve accumulation of carbohydrate and may be promoted by nutrient limitation. However, our current knowledge is inadequate for making reliable predictions concerning the onset and extent of acclimation. Many studies have sought to investigate the effects of N supply but the methodologies used generally do not allow separation of the direct effects of limited N availability from those caused by a N dilution effect due to accelerated growth at elevated pCO₂. To dissociate these interactions, wheat (Triticum aestivum L.) was grown hydroponically and N was added in direct proportion to plant growth. Photosynthesis did not acclimate to elevated pCO₂ even when growth was restricted by a low-N relative addition rate. Ribulose-1, 5-bisphosphate carboxylase/oxygenase activity and quantity were maintained, there was no evidence for triose phosphate limitation of photosynthesis, and tissue N content remained within the range recorded for healthy wheat plants. In contrast, wheat grown in sand culture with N supplied at a fixed concentration suffered photosynthetic acclimation at elevated pCO₂ in a low-N treatment. This was accompanied by a significant reduction in the quantity of active ribulose-1, 5-bisphosphate carboxylase/oxygenase and leaf N content.

Plant Physiol. (1998) 118: 573-580
Copyright Clearance Center:   0032-0889/98/118//08
© 1998 American Society of Plant Physiologists

This article has been cited by other articles:

				L. Cegelski and J. Schaefer Glycine Metabolism in Intact Leaves by in Vivo 13C and 15N Labeling J. Biol. Chem., November 25, 2005; 280(47): 39238 - 39245. [Abstract] [Full Text] [PDF]

				G.-Y. Chen, Z.-H. Yong, Y. Liao, D.-Y. Zhang, Y. Chen, H.-B. Zhang, J. Chen, J.-G. Zhu, and D.-Q. Xu Photosynthetic Acclimation in Rice Leaves to Free-air CO2 Enrichment Related to Both Ribulose-1,5-bisphosphate Carboxylation Limitation and Ribulose-1,5-bisphosphate Regeneration Limitation Plant Cell Physiol., July 1, 2005; 46(7): 1036 - 1045. [Abstract] [Full Text] [PDF]

				A. J. Bloom, D. R. Smart, D. T. Nguyen, and P. S. Searles Nitrogen assimilation and growth of wheat under elevated carbon dioxide PNAS, January 24, 2002; (2002) 22627299. [Abstract] [Full Text] [PDF]

				J. Cardoso-Vilhena and J. Barnes Does nitrogen supply affect the response of wheat (Triticum aestivum cv. Hanno) to the combination of elevated CO2 and O3? J. Exp. Bot., September 1, 2001; 52(362): 1901 - 1911. [Abstract] [Full Text] [PDF]

				R.A.C. Mitchell, J.C. Theobald, M.A.J. Parry, and D.W. Lawlor Is there scope for improving balance between RuBP-regeneration and carboxylation capacities in wheat at elevated CO2? J. Exp. Bot., February 1, 2000; 51(90001): 391 - 397. [Abstract] [Full Text]

				A. J. Bloom, D. R. Smart, D. T. Nguyen, and P. S. Searles Nitrogen assimilation and growth of wheat under elevated carbon dioxide PNAS, February 5, 2002; 99(3): 1730 - 1735. [Abstract] [Full Text] [PDF]