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Post‐photosynthetic fractionation of stable carbon isotopes between plant organs—a widespread phenomenon
Author(s) -
Badeck FranzW.,
Tcherkez Guillaume,
Nogués Salvador,
Piel Clément,
Ghashghaie Jaleh
Publication year - 2005
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.1912
Subject(s) - photosynthesis , chemistry , atmosphere (unit) , ecosystem , terrestrial ecosystem , fractionation , isotopes of carbon , organic matter , environmental chemistry , isotopic signature , botany , atmospheric sciences , isotope , ecology , total organic carbon , biology , physics , biochemistry , organic chemistry , quantum mechanics , thermodynamics
Discrimination against 13 C during photosynthesis is a well‐characterised phenomenon. It leaves behind distinct signatures in organic matter of plants and in the atmosphere. The former is depleted in 13 C, the latter is enriched during periods of preponderant photosynthetic activity of terrestrial ecosystems. The intra‐annual cycle and latitudinal gradient in atmospheric 13 C resulting from photosynthetic and respiratory activities of terrestrial plants have been exploited for the reconstruction of sources and sinks through deconvolution by inverse modelling. Here, we compile evidence for widespread post‐photosynthetic fractionation that further modifies the isotopic signatures of individual plant organs and consequently leads to consistent differences in δ 13 C between plant organs. Leaves were on average 0.96‰ and 1.91‰ more depleted than roots and woody stems, respectively. This phenomenon is relevant if the isotopic signature of CO 2 ‐exchange fluxes at the ecosystem level is used for the reconstruction of individual sources and sinks. It may also modify the parameterisation of inverse modelling approaches if it leads to different isotopic signatures of organic matter with different residence times within the ecosystems and to a respiratory contribution to the average difference between the isotopic composition of plant organic matter and the atmosphere. We discuss the main hypotheses that can explain the observed inter‐organ differences in δ 13 C. Copyright © 2005 John Wiley & Sons, Ltd.