Influence of Salicylic Acid on Stress Tolerance During Seed Germination of Triticum aestivum and Hordeum vulgare

Abstract: The relationship between compatible solutes (osmolytes) and antioxidants are the strategies that plants have developed to tolerate salt stress. Pre-treatment of wheat (Triticum aestivum L. cv) and barley (Hordeum vulgare L. cv) with Salicylic acid (SA) can be enhanced their tolerance to saline stress during germination. The alleviation of oxidative damage and increased resistance to salt stress induced by 150 mM NaCl treatments often correlate with a more efficient antioxidative defense systems and detoxification mechanisms. Pre-treatment of wheat and barley plants with salicylic acid (SA) enhanced antioxidant activities in concentration dependent manner and increased the stress tolerance of seedlings. Improved acclimation of SA-pre-treated plants to salt stress depended on the activation of the antioxidative and accumulation of ionic and non-ionic osmolytes. The present work deals with the possible role of the osmotic adaptation and oxidative defense mechanisms of wheat and barley plants with low concentrations of SA. During the germination period, a considerable increase was observed in proline levels (up to 185 % in T. aestivum and about 128 % in H. vulgare) in the seedlings subjected to saline stress (S), whereas in the SAS group, the proline increment was not significantly. Starting from the fourth day of germination, betaine levels in seedlings pretreated with Salicylic acid and then with water (SAW group) and in SAS showed a significant increase versus C and S seedlings, possibly because such a precursor promotes betaine biosynthesis. This could be