Figure 11 : Exploring the mechanism of leaf bulk cell wall O-acetylation. Simplified schematic showing acetate and its four-stable carbon isotopologues with 0 (A ), 1 (B andC ), and 2 (D ) 13C atoms. Following delivery of a 10 mM 13C2-acetate to detached poplar branches and a whole poplar tree via the transpiration stream, leaf cell walls were isolated and analyzed by1H-NMR. Note: the much more intense12C2-isotopologue signal (A) was clipped vertically in both control and13C2-acetate spectra to show the details of the satellite peaks corresponding to the remaining isotopologues which are labeled B-D.