Water channel required to facilitate the transport of water across cell membrane. Specifically expressed in roots. By salt and osmotic stress. Expressed in roots with a circadian rhythm showing an increase at the end of the night period, a peak during the first part of the light period and then a decrease. Aquaporins contain two tandem repeats each containing three membrane-spanning domains and a pore-forming loop with the signature motif Asn-Pro-Ala (NPA). Belongs to the MIP/aquaporin (TC 1.A.8) family. TIP (TC 1.A.8.10) subfamily.