The plasma membrane ATPase of plants and fungi is a hydrogen ion pump. The proton gradient it generates drives the active transport of nutrients by H(+)-symport. The resulting external acidification and/or internal alkinization may mediate growth responses. ATP + H(+)(in) + H2O = ADP + 2 H(+)(out) + phosphate Expressed in roots, stems, leaves from both vegetative and flowering plants, and flowers at early and late stages of development with highest expression levels found in flowers and root tissue. Belongs to the cation transport ATPase (P-type) (TC 3.A.3) family. Type IIIA subfamily.