Crassulacean acid metabolism influences D/H ratio of leaf wax in succulent plants
- Creators
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Feakins, Sarah J.
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Sessions, Alex L.
Abstract
This study sought to characterize hydrogen isotopic fractionation during biosynthesis of leaf wax n-alkanes in succulent plants capable of crassulacean acid metabolism (CAM). The metabolic and physiological features of CAM represent crucial strategies for survival in hot and dry climates and have been hypothesized to impact hydrogen isotope fractionation. We measured the stable carbon and hydrogen isotopic compositions (δ^(13)C and δD, respectively) of individual n-alkanes in 20 species of succulent plants from a global collection of the Huntington Botanical Gardens, San Marino, California. Greenhouse conditions and irrigation with water of constant δD value enabled determination of interspecies differences in net D/H fractionation between source water and leaf wax products. Carbon isotope ratios provide constraints on the extent of CAM vs. C3 photosynthesis and indicate a wide range of CAM use, with δ^(13)C values ranging from −33.01‰ to −18.54‰ (C_(27)–C_(33) n-alkanes) and −26.66‰ to −17.64‰ (bulk tissue). Despite the controlled growth environment, we observed ca. 90‰ interspecies range in δD values from −193‰ to −107‰. A positive correlation between δ^(13)C_(bulk) and δD_(C31) values with R^2 = 0.60 (δ^(13)C_(C31) and δD_(C31) values with R^2 = 0.41) implicates a metabolic isotope effect as the dominant cause of interspecies variation in the hydrogen isotopic composition of leaf wax n-alkanes in CAM-intermediate plants.
Additional Information
© 2010 Elsevier Ltd. Received 19 March 2010; revised 15 June 2010; accepted 10 September 2010. We gratefully acknowledge access to the collections provided by the Huntington Botanical Gardens and the assistance of their staff including J. Folsom, J. Trager, G. Lyons and S. Lahmayer. Samples were collected from the desert greenhouse by S.F. with the assistance of J. Trager. D. Leon, a high school intern with A.S. and S.F., was involved in the project and conducted the hexane extractions. M. Rincon conducted the EA analysis. We thank L. Sternberg for helpful discussions. The manuscript was improved by the comments from an anonymous reviewer. This research was supported in part by a UCAR/NOAA Global and Climate Change Postdoctoral Fellowship and funding from the University of Southern California to S.F.Additional details
- Eprint ID
- 22424
- Resolver ID
- CaltechAUTHORS:20110222-130709748
- University Corporation for Atmospheric Research
- University of Southern California
- National Oceanic and Atmospheric Administration (NOAA)
- Created
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2011-02-22Created from EPrint's datestamp field
- Updated
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2021-11-09Created from EPrint's last_modified field
- Caltech groups
- Division of Geological and Planetary Sciences