Salt-induced difference between Glycine cyrtoloba and G. max in anti-oxidative ability and K+ vs. Na+ selective accumulation

Abstract To characterize differences in soybean resistance to salt stress, two soybean species, the wild salt-tolerant soybean Glycine cyrtoloba (serial number ACC547) and the cultivated salt-sensitive soybean G. max (cv. Melrose) were treated with 0, 50, 100, or 150 mmol L − 1 NaCl for 5 days. A series of physiological parameters were determined in both shoots and roots, including content of chlorophyll (Chl) and malondialdehyde (MDA); electrolyte leakage (EL); hydrogen peroxide (H 2 O 2 ) concentration; superoxide oxygen radical (O 2 − ) production rate; activities of several enzymes including superoxide dismutase (SOD), catalase (CAT), and peroxidase (POD); and selective ion (Na + and K + ) accumulation. Our results showed that the relative salt tolerance of ACC547 was associated with lower loss of Chl content; lower MDA content, EL, H 2 O 2 concentration, and O 2 − production rate in both shoots and roots; higher POD activity caused by new isoforms in roots; and higher K + concentration and K + /Na + ratio in shoots. These results suggested that relative lower membrane injury, efficient K + vs. Na + selective accumulation, and newly induced POD isoenzymes are mechanisms of salt tolerance in soybean.