Abstract: Plant plasma membrane serves two main functions: (1) the transport of solutes (into and out of each cell), which is mainly carried out by the transporters, and (2) signal transduction, i.e., the sensing and initiation of the cellular physiological and biochemical responses. Plasma membrane transporters show rapid changes in catalytic activity in response to changes in the environment. The types, molecular properties, physiological functions and activity regulations of the plasma membrane_bound translocating proteins in plants are briefly reviewed. The responses of plasma membrane H+_ATPase, redox system, ion carriers and ion channels in plants to salt stress and the relations of these responses with salt tolerance in plants are described.