Morphological, physiological and phytochemical response of different Satureja hortensis L. accessions to salinity in a greenhouse experiment

Recently, water salinity is considered as an important factor affecting the quantity and quality of plant products. Plant response to stresses depends on the type of stress, stress intensity, plant species, etc. Many adaptation mechanisms have been developed in different accessions for coping with stress and completing the life cycle. This study is focusing on Satureja hortensis L., an annual herbal plant, which is accepted as a spice and traditional herbal medicine in Iran. The aim of this study is to investigate effects of salinity stress on the morphological, physiological, osmotic and phytochemical parameters of S. hortensis accessions. This experiment was arranged as factorial based on a completely randomized design with three replications. Factors were salinity stress, including 0 and 50 mM NaCl treatments and accessions including Rafsanjan, Zarand, Shahr-e Babak, Sirjan, Kerman, Baft, Jiroft, Bardsir and Kahnuj. All accessions showed significant reduction in their height, leaf area, shoot fresh weight (SFW), shoot dry weight (SDW), total chlorophyll (TChl), chlorophyll a (Chl a), chlorophyll b (Chl b), carotenoids, K, Ca and significant enhancement in Na, Cl, proline, total soluble carbohydrate (TSC), total phenolic compounds (TPC), essential oil content and its main components under the salinity stress. Results also show that different accessions have different responses to the salinity stress. We also identified twenty five different compounds in this oil; the majority of them were carvacrol (19-46.6%), gamma-terpinene (11.59-24.8%), p-cymene (9.84-34.56%), myrcene (1.4-2.78%) and beta-pinene (1.20-1.91%). According to our results, Rafsanjan, Zarand and Kahnuj accessions showed more resistance to the salinity stress. Accumulating more osmolytes, essential oil, K and Ca, which caused more dry mass production, may cause increasing their resistancy toward the salinity stress.