Growth and Physiological Responses of Pseudolysimachion pusanensis (Y. N. Lee) Y. N. Lee to NaCl Treatment

Background and objective: This study was conducted to determine the effect of NaCl on the growth, antioxidants (superoxide dismutase, proline), maximum quantum yield, and chlorophyll contents of Pseudolysimachion pusanensis. Methods: Five levels of NaCl concentrations (0, 50, 100, 200, 400 mM) were used for treatment. Results: The growth according to NaCl concentrations was highest at 50 and 100 mM, but root growth declined before the top from 200 mM or higher. The increase in NaCl concentrations also led to the increase in SOD and proline content compared to the control plot, whereas it decreased chlorophyll content. There was no difference in the maximum quantum yield at 0, 50, 100, and 200 mM, but it decreased at 400 mM. Conclusion: The results proved that P. pusanensis showed an increase in SOD and proline content at 50 and 100 mM of NaCl treatment compared to the control plot, indicating that it receives salt stress, but the growth was excellent at 50 and 100 mM. In addition, there was no difference in top growth up to 200 mM compared to the control plot, and there was no significant difference in the maximum quantum yield, which proved that P. pusanensis has strong tolerance to salt stress.