Effects of Salicylic Acid on Photosynthetic Pigments, Osmolytes, and Antioxidant Enzyme Activities in White Savory (Satureja mutica Fisch.) Exposed to Various Salt Levels

Document Type : Research paper

Authors

Department of Biology, Faculty of Science, Bu-Ali Sina University, Hamadan, Iran

Abstract

White savory (Satureja mutica Fisch.) is an oil-bearing plant with applications in traditional medicine, pharmaceutical industries, and food additives in homemade dishes. The current research comprised a greenhouse experiment in a factorial arrangement based on a completely randomized design (CRD). It included four salinity levels (0, 50, 100, and 150 mM NaCl), two salicylic acid (SA) levels (0 and 2 mM), and three replicates. By increasing the NaCl concentration, the content of chlorophyll a, chlorophyll b, total chlorophyll, and carotenoid significantly declined. Increasing NaCl up to 100 mM caused a significant increase in proline and soluble protein content. The amount of proline at 150 mM NaCl showed no significant change compared to 100 mM NaCl, but the soluble protein sharply decreased at 150 mM NaCl. The enzymatic activities of superoxide dismutase, catalase, and peroxidase significantly increased in response to higher NaCl concentrations. Saturated water deficiency increased significantly, and leaf fresh and dry weights decreased substantially at 100 and 150 mM NaCl. SA enhanced chlorophyll a, chlorophyll b, total chlorophyll, carotenoid content, and leaf fresh and dry weight, depending on the NaCl treatments. SA applications considerably boosted peroxidase and catalase activities despite the presence of NaCl at any concentration. Also, SA significantly improved superoxide dismutase activity at 50 and 100 mM NaCl but could not counter its decrease when the NaCl level was 150 mM. SA significantly reduced saturated water deficiency and proline content despite any of the NaCl treatments. SA mitigated the adverse effects of NaCl on S. mutica by improving antioxidant activity, photosynthetic pigments, and physiological characteristics. 

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