Adventitious root formation (ARF) is an essential step in vegetative propagation. In the understanding of ARF, substantial progress was made more than 7 decades ago by the elucidation of the effect of auxin, but after that progress was limited. In recent decennia, the understanding of developmental processes in plants has benefited much from research of Arabidopsis mutants. We will examine ARF in selected Arabidopsis mutants. Establishment of an ARF system in Arabidopsis is needed prior to mutant analysis. Arabidopsis is a rosette plant, so ‘normal’ cuttings or microcuttings cannot be examined. In the present study various explant types are being examined, viz., hypocotyls, flower stems and petioles.