Salinity is one of the most extreme abiotic stress factors that negatively affect the development and productivity of plants. The salt-induced injuries depend on the salt tolerance of the plant species, salt concentration, time of exposure and developmental stage. Here, we report on the response of pea plants (Pisum sativum L. cv Ran 1) to exposure to increasing salt concentrations (100, 150 and 200 mM NaCl) for a short time period (5 days) and the ability of the plants to recover after the removal of salt. The water content, membrane integrity, lipid peroxidation, pigment content and net photosynthetic rate were determined for the pea leaves of the control, treated and recovered plants. Salt-induced alterations in the primary photosynthetic reactions and energy transfer between the main pigment-protein complexes in isolated thylakoid membranes were evaluated. The pea plants were able to recover from the treatment with 100 mM NaCl, while at higher concentrations, concentration-dependent water loss, the disturbance of the membrane integrity, lipid peroxidation and an increase in the pigment content were detected. The net photosynthetic rate, electron transport through the reaction centers of PSII and PSII, activity of PSIIα centers and energy transfer between the pigment-protein complexes were negatively affected and were not restored after the removal of NaCl.
Keywords: Pisum sativum; membrane stability; photosynthetic performance; primary photosynthetic reactions; salt stress.