Plant tissues artificially labeled with 13C are increasingly used in environmental studies to unravel biogeochemical and ecophysiological processes. However, the variability of 13C-content in labeled tissues has never been carefully investigated. Hence, this study aimed at documenting the variability of 13C-content in artificially labeled leaves.
European beech and Italian ryegrass were subjected to long-term 13C-labeling in a controlled-environment growth chamber. The 13C-content of the leaves obtained after several months labeling was determined by isotope ratio mass spectrometry.
The 13C-content of the labeled leaves exhibited inter- and intra-leaf variability much higher than those naturally occurring in unlabeled plants, which do not exceed a few per mil. This variability was correlated with labeling intensity: the isotope composition of leaves varied in ranges of ca 60‰ and 90‰ for experiments that led to average leaf 13C-content of ca +15‰ and +450‰, respectively.
The reported variability of isotope composition in 13C-enriched leaves is critical, and should be taken into account in subsequent experimental investigations of environmental processes using 13C-labeled plant tissues. Copyright © 2013 John Wiley & Sons, Ltd.