The export of auxin from tips and from sections of Avena coleoptiles as influenced by red light

Red light causes an increase of auxin export from subapical sections of Avena coleoptiles and simultaneously decreases the export from tips. Also the imposition of a physical barrier on the export of auxin from tips results in a reduced export of auxin after the barrier has been removed. This shows that red light may exert an influence by way of changes in transport properties in the coleoptile.