In grass cell walls, ferulic acid is esterified to arabinoxylan residues forming dimers via the oxidative coupling reactions, cross-linking arabinoxylan chains. Ferulate cross-linking is suggested to play a role in different plant processes. In the current study we investigated the role of cell wall feruloylation in internode expansion in maize using transgenic plants, which levels of cell wall ferulates have been reduced by targeted expression of Aspergillus niger ferulic acid esterase A to the apoplast