Salinity stress cause to several chemical, physiological and morphological modifications in plants -Mehrizi et al., 2011-. Salicylic acid -SA- is one of the most important plant growth regulator substances that regulate physiological growth and development of plant and its application under stress condition cause to create tolerance in plants -Dianat et al., 2016-. In order to study the effect of SA o some physiological and biochemical characteristics of Lippia citroidora under NaCl stress, a pot factorial experiment based on completely randomized design with four levels of irrigation water -0, 50, 100, 150 mM NaCl- and four levels of SA -0, 150, 300, 450 mg/L- in three replications was performed. The results showed that interaction effects of salinity and SA on photosynthetic pigments, soluble carbohydrate, total phenol, protein amounts and catalase -CAT-, peroxidase -POD- and superoxide dismutase -SOD- activities were significant. The mean comparison indicated that SA application caused to decrease glycine betaine, protein, CAT, POD and SOD activities and increase photosynthetic pigments, soluble carbohydrate, total phenol and proline content. Generally, the results of this study showed that foliar application of SA improved harmful effects of salinity partly. According to the findings of this experiment, SA usage at 300 and 450 mg/L cause to tolerate this plant to stress condition through regulation and improvement of physiological and biochemical characteristics.

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