Salicornia europaea L. regulates salinity stress through production of saponins and antioxidant compounds

Salicornia europaea L. is a common halophytic plant species distributed in many saline soils and habitats, including margins of many wetlands. Salicornia europaea grows around Mighan Wetland, a natural desert ecosystem in central Iran with fluctuating water levels due to constant heat and severe wind throughout the year. Although, aspects of biology and ecology of halophytes growing in Mighan Wetland have been studied, information on Salicornia europaea is scarce. This research was carried out to compare both enzymatic and non- enzymatic antioxidants of Salicornia europaea L. Soil and whole plant samples were collected in triplicate four equidistant locations from Wetland edge in May, 2016. Soil samples were analyzed for its pH and electric conductivity (EC). Plant leaves were analyzed for activities of stress-related enzymatic (peroxidase and catalase) antioxidants and contents of non-enzymatic antioxidants (flavonoids and anthocyanins), cell membrane integrity via measuring lipid peroxidation through Malondialdehyde production (MDA) and changes in content of leaf saponin. Analysis of variance (ANOVA), Duncan Post-hoc tests and correlation tests were performed using the SPSS.22 statistical program. Results showed that peroxidase activity reduced and contents of total flavonoids, anthocyanin, saponin and MDA as well as activity of catalase hiked with increasing EC. The study showed that S. europaea reacts to salinity stress by restricting catalase in proxisomes to limit ROS production, accumulating carbohydrates in cytosol to improve osmoregulation and producing flavonoids, anthocyanine and saponins as complementary osmo regulators and defensive agents.