Antioxidant responses and sodium accumulation in Juncus effusus and Schoenoplectus lacustris exposed to road salt: implications for freshwater remediation

Abstract

Road salt pollution is an emerging threat to freshwater ecosystems, especially in temperate regions where sodium chloride (NaCl) is widely used for winter road maintenance. This study assessed the antioxidant response and sodium accumulation potential of two native plant species, Juncus effusus and Schoenoplectus lacustris , to evaluate their suitability for phytodesalinisation. Plants were exposed to NaCl at concentrations of 200 and 1000 mg/L under controlled conditions. In J. effusus , exposure to 1000 mg/L NaCl caused a significant increase in lipid peroxidation (TBARS) and a decrease in catalase activity, accompanied by elevated glutathione (GSH) levels. In contrast, S. lacustris maintained stable TBARS levels and showed significantly higher total non-enzymatic antioxidant capacity under control conditions, although this capacity declined under salinity stress. Notably, J. effusus accumulated significantly more mg Na + /g dry weight compared to S. lacustris , indicating greater ion sequestration capacity. Despite differences in oxidative stress responses, both species exhibited effective antioxidant defences and sodium uptake, suggesting their potential utility in nature-based solutions such as constructed wetlands to mitigate road salt contamination in urban freshwater systems.