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, trichome cells of the rosette leaves, vascular tissues of the flower petals, stigma, stamens (anthers and filaments), pollen and the top and bottom (receptacle) of siliques. Aquaporins contain two tandem repeats each containing three membrane-spanning domains and a pore-forming loop with the signature motif Asn-Pro-Ala/Thr (NPA). Belongs to the MIP/aquaporin (TC 1.A.8) family. SIP (TC 1.A.8.10) subfamily.