JXB Advance Access originally published online on October 9, 2006
Journal of Experimental Botany 2006 57(14):3837-3845; doi:10.1093/jxb/erl149
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
RESEARCH PAPER |
Respiratory carbon metabolism in the high mountain plant species Ranunculus glacialis
Station Alpine Joseph Fourier, UMS UJF CNRS 2925-Col du Lautaret, 05480 Villar d'Arène, France
1Departament de Biologia Vegetal, Universitat de Barcelona, 645 Diagonal Av, 08028 Barcelona, Spain
2Laboratoire d'Ecologie, Systématique et Evolution, CNRS UMR 8079, IFR 87, Université Paris XI, 91405 Orsay Cedex, France
3Laboratoire d'Ecologie Alpine, CNRS Université Joseph Fourier BP 53, 38041 Grenoble Cedex 9, France
4Laboratoire de Physiologie Cellulaire Végétale, Unité Mixte de Recherche 5168, Commissariat à l'Energie Atomique-Grenoble, 38054 Grenoble Cedex 9, France
* To whom correspondence should be addressed. E-mail: salvador.nogues{at}ub.edu
Very little is known about the primary carbon metabolism of the high mountain plant Ranunculus glacialis. It is a species with C3 photosynthesis, but with exceptionally high malate content in its leaves, the biological significance of which remains unclear. 13C/12C-isotope ratio mass spectrometry (IRMS) and 13C-nuclear magnetic resonance (NMR) labelling were used to study the carbon metabolism of R. glacialis, paying special attention to respiration. Although leaf dark respiration was high, the temperature response had a Q10 of 2, and the respiratory quotient (CO2 produced divided by O2 consumed) was nearly 1, indicating that the respiratory pool is comprised of carbohydrates. Malate, which may be a large carbon substrate, was not respired. However, when CO2 fixed by photosynthesis was labelled, little labelling of the CO2 subsequently respired in the dark was detected, indicating that: (i) most of the carbon recently assimilated during photosynthesis is not respired in the dark; and (ii) the carbon used for respiration originates from (unlabelled) reserves. This is the first demonstration of such a low metabolic coupling of assimilated and respired carbon in leaves. The biological significance of the uncoupling between assimilation and respiration is discussed.
Key words: Carbon isotopic labelling, malate, photosynthesis, Ranunculus glacialis, respiration
CiteULike 
Connotea 
Del.icio.us What's this?
This article has been cited by other articles:
|
|
 |
|
  F. Baptist, G. Tcherkez, S. Aubert, J.-Y. Pontailler, P. Choler, and S. Nogues 13C and 15N allocations of two alpine species from early and late snowmelt locations reflect their different growth strategies J. Exp. Bot., July 1, 2009; 60(9): 2725 - 2735. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 N. Gomez-Casanovas, E. Blanc-Betes, M. A. Gonzalez-Meler, and J. Azcon-Bieto Changes in Respiratory Mitochondrial Machinery and Cytochrome and Alternative Pathway Activities in Response to Energy Demand Underlie the Acclimation of Respiration to Elevated CO2 in the Invasive Opuntia ficus-indica Plant Physiology, September 1, 2007; 145(1): 49 - 61. [Abstract] [Full Text] [PDF]
|
|