Figure 3.

Root meristem development. (a) Schematic of the Arabidopsis root meristem. Colours represent the localization of the homeodomain transcription factor WOX5 (red) in the quiescent centre, the receptor kinase ACR4 (green) in columella stem cells and columella cells and the peptide ligand CLE40 (blue) in columella cells. The stem cell niche is outlined in orange. (b) Conceptual model of distal stem cell fate regulation in the root meristem. Arrows indicate positive regulation and barred arrows indicate negative regulation.