The role of ethylene in root hair growth in Arabidopsis

Ethylene promotes root hair development in many higher plants. Recently the role of ethylene has been investigated in Arabidopsis because of the range of genetic resources available in this species. Root hairs in the Arabidopsis root form on specialized epidermal cells (trichoblasts) located in the cleft between underlying cortical cells. Hairless epidermal cells develop from atrichoblasts that are located over single cortical cells. Ethylene not only promotes root hair outgrowth but also causes cells that are normally hairless to form root hairs. This suggests that ethylene may play a dual function in the formation of root hairs. Firstly it may play a role in hair initiation and secondly may be required for the elongation of hairs. Alternatively it may suggest that these are two parts of the same process.