Water channel required to facilitate the transport of water across cell membrane. Expressed in roots and above ground. Expressed in elongating regions of the root tips, cotyledons, minor veins and hydathode cells of the rosette leaves. Weakly expressed in vascular tissues of the flower petals, filaments of stamens, upper part of the styles and receptacles of the siliques. Aquaporins contain two tandem repeats each containing three membrane-spanning domains and a pore-forming loop with the signature motif Asn-Pro-Ala/Cys (NPA). Belongs to the MIP/aquaporin (TC 1.A.8) family. SIP (TC 1.A.8.10) subfamily.