Response of photosynthesis of Pisum sativum to salt stress as affected by methyl jasmonate

10-5 M methyl jasmonate (JA-Me) treatment itself did not considerably change the 14CO2 fixation, parameters of room temperature chlorophyll fluorescence induction, proline content, and Na+ as well as Cl- accumulation. Salt stress (30 mM NaCl) lead to a decrease of both 14CO2 fixation and relative water content, and to an increase of proline content. Immediate nonvariable fluorescence (F0) also increased and the variable to maximal fluorescence ratio (Fv/Fm) decreased. Pretreatment with JA-Me for 3 d before salt treatment diminished the inhibitory effect of NaCl on the rate of 14CO2 fixation, protein content, and activity and content of ribulose-1,5-bisophosphate carboxylase/oxygenase. The Na+ and Cl- contents in leaves decreased in JA-Me pretreated plants. The JA-Me pretreatment prevented the increase of F0 level and restored the values of Fv/Fm.