Fig. 4

Short-range 2D NMR (HSQC) spectra revealing lignin subunits (top) and inter-unit linkages (bottom). Top: aromatic regions at δ _C/δ _H 100-140/6.0-8.0 ppm; bottom: side chain regions at δ _C/δ _H 50–90/2.5–6.0 ppm. Lignin subunits and inter-unit linkages are labeled with letters corresponding to given color-coded structures