Strategies used by two goji species, Lycium ruthenicum and Lycium barbarum, to defend against salt stress

The perennial shrub genus goji, particularly the wild species Lycium ruthenicum, has a high tolerance to salinity, but the adaptation strategy used by this salt-tolerant species is poorly understood. Here, the differential responses of cultivated goji Lycium barbarum and wild Lycium ruthenicum to salinity were investigated to study their stress tolerance and understand their salt-stress tolerance strategies. Physiological traits, including biomass, malondialdehyde content, and proline content were analyzed under different NaCl concentrations. Results of the biomass analysis indicated that moderate NaCl treatment enhanced growth compared with nonsalinized control. However, malondialdehyde accumulated under the 200 mM NaCl treatment, particularly in L. barbarum. Proline levels increased, whereas the SPAD value and relative water content were stable. After L. barbarum and L. ruthenicum seedlings were treated with 200 mM NaCl for 16 days, ion accumulations and ion flux characteristics were analyzed. L. ruthenicum evolved a more efficient mechanism to maintain K+/Na+ homeostasis than L. barbarum because the former had an improved ability to regulate ion transport.