Extended Data Fig. 5: Comparisons of methoxyl ∆13CH2D, δ13C, and concentration, colored by sample set.
From: Isotopic evidence for elevated photorespiration during the last glacial period
a Methoxyl ∆13CH2D versus methoxyl concentration. b Methoxyl ∆13CH2D versus methoxyl δ13C. c Methoxyl δ13C versus methoxyl concentration. Methoxyl δ13C and concentration (in wt.%) are both potential tracers of O-demethylation reactions37. We interpret the lack of correlation for ∆13CH2D vs. δ13C and ∆13CH2D vs. concentration to indicate that any partial O-demethylation (if it occurred) did not influence the ∆13CH2D values of these samples. Error bars on ∆13CH2D omitted for clarity (typically ± 0.25‰, 1 s.e.m. of measurement). Error bars on δ13C and wt.% methoxyl are smaller than symbol size.
