Figure 8.
Model for Auxin Action during Ethylene-Regulated Root Growth.
The model provides a spatial framework on which to place auxin components required for ethylene responses in roots. The schematic diagram of the Arabidopsis root apex is overlaid with the sites of action of auxin biosynthesis (WEI2/ASA1 and WEI7/ASB1) and transport (AUX1) components required for ethylene inhibition of root growth. Small arrows denote the basipetal flow of auxin from the root apex via the lateral root cap to the elongation zone. Sites of ethylene-responsive gene expression are denoted by large horizontal arrows. We also highlight that the dominant gain-of-function mutation axr3-1/iaa17 can disrupt ethylene inhibition of root growth in elongation zone tissues. Vertical arrows either represent the time required or distance moved by root cells as they progress through meristematic and elongation zones.
