Effect of salt stress on some physiological and biochemical parameters of two Salvia species

Salinity is considered as one of the main limiting factors for growth and production of several agricultural crops all over the world. Also، salinity influences the growth and also synthesis of secondary metabolites of medicinal plants. Salvia viridis and Salvia spinosa are two aromatic species which belong to Salvia genus from Lamiaceae family. As the mechanisms of salt stress tolerance and also the effect of salinity on growth and production of secondary metabolites in these two salvia species have not been studied yet، the effects of salt stress on growth parameters and the essential oil composition in these plants were analyzed. Seedlings of two mentioned species، two weeks after germination and growth، were grown at different levels of NaCl including: 0 (control)، 20، 40، 60 and 80 mM NaCl at Hogland medium in a hydroponic system. After four weeks، later، the growth parameters such as: shoot and root dry weight، Na+ and K+ concentrations، the amount of proline and soluble sugars، were measured. Also، the essential oil composition was compared between control and salt stress in S. viridis. Results showed that، by increasing of salt stress levels، shoot and root dry weight of both species were decreased. Salt stress resulted in increasing of soluble sugars and proline concentrations in aerial parts of both species. However، this increase in S. spinosa was a little higher than other species. K+ content was also decreased by salt stress in both species although in S. spinosa this decrease was less than S. viridis. Salt stress resulted in increasing of some essential oil compounds such as: -pinene، -3-carene and linalool in S. viridis in compared to the control plants. It could be concluded that less sensitivity of S. spinosa to salt stress can be attributed to more accumulation of proline and soluble sugars and inhibition of K+ decreasing under salt stress in this species.