Investigation Reducing Detrimental Effects of Salt Stress on Morphological and Physiological Traits of (Thymus vulgaris) by Application of Salicylic Acid

Abstract Salicylic acid (SA) is a naturally occurring plant hormone that has positive effects on growth and tolerance to biotic and abiotic stresses, especially salinity in plants. To evaluate the effects of SA and salt stress on some morphological and physiological traits and quantitative activities of antioxidant enzymes on thyme (Thymus vulgaris), was conducted a factorial pot experiment based on completely randomized design with four levels of SA (0t 150, 300 and 400 ppm) and four levels of salinity stress (0, 50, 100 and 150 mM, induced by NaCl) and three replicates. The results showed that salinity increased soluble sugars, quantitative activities of peroxidase and fresh weight and decreased stem height, leaf area and protein content. Interaction effects between salt stress and SA treatments resulted to greater leaf area, fresh weight, protein content and quantitative activities of catalase and peroxidase, significantly. Based the results of this study, leaf sparing of SA, improve physiological traits and alleviate salt stress effects through influencing physiological processes as increasing of antioxidant activity enzymes and soluble sugars content in Thymus vulgaris.