Toxicological responses in halophyte Suaeda salsa to mercury under environmentally relevant salinity

Mercury is a highly risky heavy metal contaminant in intertidal zones in the Yellow River Delta (YRD). Suaeda salsa is a native halophyte in the YRD. In this work, we investigated the toxicological effects of mercury (20 mu g L-1) in S. salsa under environmentally relevant salinity (500 mM). The metabolic responses included the increased amino acids and decreased succinate, fructose, glucose, fumarate and ferulate in above-ground part of S. salsa exposed to mercury. The expression levels of INPS, CMO, BADH, CAT and GPx were elevated in above-ground part of S. salsa after combined Hg and salinity exposure. Increased activities of antioxidant enzymes including SOD, POD and CAT were uniquely observed in salinity-treated samples. Our results indicated potential oxidative stresses and disturbances in protein bio-degradation and energy metabolism induced by mercury in S. salsa. Additionally, both synergistic and antagonistic effects were observed in S. salsa exposed to combined mercury and salinity. (C) 2012 Elsevier Inc. All rights reserved.