Table 1 .1H-NMR isotopologue analysis results for acetate released following saponification of isolated leaf cell wall samples from (a ) 3 detached branches (one per tree, N = 3) treated with 10 mM 13C2-acetate solution for 2 days as well as (b ) canopy leaf (N = 3) samples from a 2-year old tree following continuous diurnal injections of the 10 mM13C2-solution into the xylem at the base of the tree for 7 days (night: 70 µL/min, day: 150 µL/min). Following saponification of the cell wall isolates, the values were obtained by integrating the area of the free acetate signals (corresponding to each of the four isotopologues shown in Fig. 10 ), and calculating the fraction of each acetate isotopologue to the total (Fexperiment = peak area acetate isotopologue/peak area of total acetate isotopologues), and reporting the ratio of Fexp to that from natural abundance fractions (Fnatural abundance). Note, statistically significant changes in Fexperiment/Fnatural abundance (*), no statistically significant changes (ns).