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Assessing the stable carbon isotopic composition of intercellular CO 2 in a CAM plant using gas chromatography‐combustion‐isotope ratio mass spectrometry
Author(s) -
Nogués Salvador,
Aranjuelo Iker,
Pardo Antoni,
AzcónBieto Joaquim
Publication year - 2008
Publication title -
rapid communications in mass spectrometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.528
H-Index - 136
eISSN - 1097-0231
pISSN - 0951-4198
DOI - 10.1002/rcm.3460
Subject(s) - chemistry , isotope ratio mass spectrometry , mass spectrometry , fractionation , stable isotope ratio , isotopes of carbon , environmental chemistry , gas chromatography , rubisco , isotope , carbon dioxide , carbonic anhydrase , carbon fibers , gas chromatography–mass spectrometry , combustion , chromatography , photosynthesis , total organic carbon , enzyme , biochemistry , organic chemistry , physics , materials science , quantum mechanics , composite number , composite material
Abstract Most of the literature focused on internal CO 2 (Ci) determinations in plants has used indirect methods based on gas‐exchange estimations. We have developed a new method based on the capture of internal air gas samples and their analysis by gas chromatography‐combustion‐isotope ratio mass spectrometry (GC‐C‐IRMS). This method provided a direct measure of intercellular CO 2 concentrations combined with stable carbon isotopic composition in O. ficus‐indica plants. Plants were grown at both ambient and elevated CO 2 concentration. During the day period, when the stomata are closed, the Ci was high and was very 13 C‐enriched in both ambient and elevated CO 2 ‐grown plants, reflecting Rubisco's fractionation (this plant enzyme has been shown to discriminate by 29‰, in vitro , against 13 CO 2 ). Other enzyme fractionations involved in C metabolism in plants, such as carbonic anhydrase, could also be playing an important role in the diurnal δ 13 C enrichment of the Ci. During the night, when stomata are open, Ci concentrations were higher in elevated (and the corresponding δ 13 C values were more 13 C‐depleted) than in ambient CO 2 ‐grown plants. Copyright © 2008 John Wiley & Sons, Ltd.