Fig. 4: LC-MS/MS 13C-labeling analysis of phosphoglyceric acid (PGA), serine, and methionine extracted from P. trichocarpa leaves following 2-day gas exchange studies under a 13CO2 and 21% O2 atmosphere.
From: The ‘photosynthetic C1 pathway’ links carbon assimilation and growth in California poplar
a % total abundance ratio plot of [13C3/(13C3 + 12C3)]-PGA, [13C3/(13C3 + 12C3)]-serine, and [13C/12C]-methionine from control leaves exposed to a natural abundance 12CO2 atmosphere (n = 10), and leaves exposed to 13CO2 over two diurnal cycles (n = 12). The red vertical lines are the theoretical natural abundance ratios and * indicates significant difference by one tailed t test at P < 0.001. PGA was confirmed by RT, and m/z comparison with pure reference standard, while serine and methionine were confirmed with RT, m/z and MSMS. Also shown are the mirror plots comparing fragmentation patterns of leaf methionine (b) and serine (c) from 12CO2 and 13CO2 exposed leaves. Serine and methionine carbon atoms within each fragment are shown as previously determined26. Green fragments indicate matching ions within 15 ppm and blue and purple fragments indicate that the lower ion is within 15ppm of the expected 13C-labeled fragment isotopologue (see legend).
