May be involved in the limitation of water flow through the outer epidermal cell wall, either by direct modification of wall structure or as a signal instructing the protoplast to restrict water transport across the cell wall. In 14-day old seedlings, expressed in the epidermis and apical dome of the shoot and in the hypocotyl, cotyledon and epidermis of the root. In developing seeds, expressed in both the inner and outer epidermis of the integument.