Effect of Exogenous Salicylic Acid on Growth Parameters, Gas Exchange, and Photosynthetic Yields in Salt-Stressed Vicia faba L. Plants

This study aimed to evaluate the potential effect of salicylic acid (SA) on the photosynthetic performance of faba bean ( Vicia faba L.) plants under salt stress conditions. For this purpose, two salinity levels (0 and 120 mM) combined with two concentrations of SA (0 and 0.5 mM) were applied. Results showed that salt stress decreases the growth and gas exchange parameters ( P N , C i , g s , and T r ). Chlorophyll fluorescence imaging parameters showed a decrease in the effective photochemical quantum yield of PSII (YPII), photochemical quenching (qP), and electron transport rate (ETR), while the regulated (Y(NPQ) and unregulated dissipation energy Y(NO)) were increased under stress conditions. However, exogenous SA application under salt stress decreases the non-regulated dissipation and improves photosynthetic performance (Y(PSII), ETR, qP, and Y(NPQ)), growth, and gas exchange parameters. Consequently, SA application had a beneficial effect on the faba bean tolerance to salt stress and can be recommended for field application with low concentration.