The investigation of physiological and biochemical effects at endogenous phytohormone levels of salicylic acid treatment in barley (Hordeum vulgare L.) cultivars exposed to salt stress

In the present study, the effects of salicylic acid (SA) on growth parameters, leaf relative water content (RWC), photosynthetic pigment contents, proline contents, antioxidant enzymes including superoxide dismutase (SOD), peroxidase (POX), catalase (CAT), ascorbate peroxidase (APX) and glutathione reductase (GR) and endogenous phytohormones including indole-3-acetic acid (IAA), t-zeatine, abscisic acid (ABA), jasmonic acid (JA) and ethylene were investigated in leaves and roots of Akhisar-98, Erginel-90 ve Kalaycı-97 cultivars of barley (Hordeum vulgare L.; 2n=14) under salt stres. SA alleviated salt-induced decreases in growth parameters, contents of water and phtosynthetic pigment of barley cultivars. It was determined that the amino acid proline involved in osmotic adjustment was more accumulated in tolerant cultivars than susceptible and SA application was found to increase osmotolerance. While the severity of the salt stress increased, SOD and POX activities in Kalaycı, GR activity in Erginel and CAT activity in Akhisar were also increased. Due to the fact that SA treatment caused decreasing of CAT activity, the connection was determined between ABA levels and SA. When IAA levels were found to be high in salt sensitive cultivars, in a similar manner tZ decreased and, the antagonist relation was determined between them. With SA treatment, as a result of increasing concentrations of salt intensity in relation with decreasing water content, increment in ABA and decline in JA levels were recorded. Eventually, it was exhibited that NaCl and/or exogenous SA induced the achievement more tolerance to salt at especially application before salt stress. These findings indicated that Kalaycı was more tolerant and Akhisar was more susceptible to salt stress.