Growth characteristics of Mexican oregano (Lippia berlaadieri Schauer) under salt stress

摘要

This study evaluated growth patterns of Mexican oregano (Lippia berlandieri) under salt stress and tested the hypothesis that this species is salt tolerant. Plants were grown in Hoagland solution with no NaCl added (control) and with increasing NaCl concentrations added to produce osmotic potentials of -0.30, -0.45, -0.60, -0.90, and -1.20 MPa. Relative growth rate decreased linearly and leaf weight decreased 9-fold as osmotic potential decreased from control to -1.20 MPa. We therefore concluded that, compared to other non-halophytes, Mexican oregano is only moderately tolerant of salinity Root growth was less affected by salinity than leaf and stem growth. Relative growth rate of Mexican oregano varied from 0.01 to 0.08 g/g/d. These low values suggest a slow recovery process for plants in native stands subject to continuous harvesting.