Fig. 1. Lignin precursors (i.e., monolignols) used to form DHP-CWs with primary maize walls and major ferulate and diferulate esters forming xylan–xylan and xylan–lignin cross-linked structures in DHP–CWs. ‘Ara’ are arabinofuranosyl residues on arabinoxylans. Dotted arrows indicate potential sites for coupling with monolignols during lignin polymerization.