Water channel required to facilitate the transport of water across cell membrane; mercury-insensitive (By similarity). Promotes primary root elongation and root hair formation (PubMed:24606771). 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:24606771, PubMed:34512687). Regulates also the expression of abscisic acid (ABA)-responsive genes during dehydration and salt stresses (PubMed:24606771, PubMed:34512687). Expressed in leaves, roots, stems, flowers and fruits, with highest levels in roots. Present in fruit throughout the development, but fades out during ripening. Induced by salt (NaCl) and water deprivation (PubMed:24606771). Repressed by chilling treatment (PubMed:24606771, PubMed:26307965). Seems to be regulated by several transcription factor genes, including MaERF14, MaDREB1G, MaMYB1R1, MaERF1/39, MabZIP53 and MaMYB22 under salt or cold stresses (PubMed:34512687). 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.