Salicylic acid and hydrogen peroxide pretreatments alleviate salt stress in faba bean (Vicia faba) seeds during germination

The effect of salycilic acid (SA) and hydrogen peroxide (H₂O₂) pretreatments on germination of faba bean (Vicia faba) seeds was studied under salt (NaCl) stress. Seed germination and primary root elongation decreased with increasing salt concentrations. NaCl application increased starch, sugar and malondialdehyde (MDA) contents. However, there were decreases in amylase activity in the cotyledons, total lipid (TL) content and all fatty acids except C18:2 in germinating seeds. Both SA and H₂O₂ treatments overcame the inhibitory effect of salt stress on seed germination. The increase in germination percentage and primary root elongation under salt stress was associated with enhanced levels of total sugars and reduced content of starch as a result of induced total amylase activity in the cotyledons of germinating seeds. The application of SA and H₂O₂ was effective in decreasing MDA. It also increased SOD and GPOX antioxidant activities, TL content and especially the C18:3 fatty acid. SA and H₂O₂ priming is a potential effective physiological technology to improve germination under salt stress. This enhancing effect is attributed to inducing starch mobilisation to supply sufficient energy for germination, protecting cell functioning and integrity via induction of antioxidant enzymes, and accumulation of C18:3 fatty acid involved in membrane fluidity.