Salt stress responses of higher plants : The role of proton pumps and Na+/H+-antiporters

Summary In salt-stressed higher plants NaCl may either be excluded from the cells or sequestered into the vacuole. Different pathways may dominate in different plants and different organs of the same plant. The proteins involved in salt transport across the plasma membrane and the tonoplast i.e. proton pumps and Na + /H + -antiporters have been identified. Progress in cloning of the P-type H + -ATPase, the V-type H + -ATPase, and the vacuolar H + -ATP i ase has provided important tools for the study of the moleculat mechanism's involved in ion sequestration. However, not a single plant has as yet been studied in sufficient detail to allow a comprehensive evaluation of the relative importance of individual transport processes for the salt tolerance of an intact plant. This review summarizes our present as yet limited knowledge and identifies promissing areas for future research.