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Leaf water oxygen isotope measurement by direct equilibration
Author(s) -
Song Xin,
Barbour Margaret M.
Publication year - 2016
Publication title -
new phytologist
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.742
H-Index - 244
eISSN - 1469-8137
pISSN - 0028-646X
DOI - 10.1111/nph.13962
Subject(s) - isotopes of oxygen , oxygen , isotope , chemistry , range (aeronautics) , environmental chemistry , analytical chemistry (journal) , oxygen 18 , stable isotope ratio , materials science , physics , nuclear chemistry , organic chemistry , quantum mechanics , composite material
Summary The oxygen isotope composition of leaf water imparts a signal to a range of molecules in the atmosphere and biosphere, but has been notoriously difficult to measure in studies requiring a large number of samples as a consequence of the labour‐intensive extraction step. We tested a method of direct equilibration of water in fresh leaf samples with CO 2 , and subsequent oxygen isotope analysis on an optical spectrometer. The oxygen isotope composition of leaf water measured by the direct equilibration technique was strongly linearly related to that of cryogenically extracted leaf water in paired samples for a wide range of species with differing anatomy, with an R 2 of 0.95. The somewhat more enriched values produced by the direct equilibration method may reflect lack of full equilibration with unenriched water in the vascular bundles, but the strong relationship across a wide range of species suggests that this difference can be adequately corrected for using a simple linear relationship.