Water channel required to facilitate the transport of water across cell membrane; mercury-insensitive (By similarity). Contributes to the tolerance to multiple abiotic stresses including salt (NaCl), cold and water deprivation, by modulating cytosolic K(+)/Na(+) ratio, maintaining osmotic balance, and reducing membrane injury (e.g. oxidative injury) (PubMed:23745761). Barely detectable in roots, leaves and fruits. Aquaporins contain two tandem repeats each containing three membrane-spanning domains and a pore-forming loop with the signature motif Asn-Pro-Ala (NPA). Can be used to improve resistance to abiotic stresses such as cold, drought and salt. Belongs to the MIP/aquaporin (TC 1.A.8) family. PIP (TC 1.A.8.11) subfamily.