Critical concentration of salt stress in Stenotaphrum secundatum

The objective of this study was to identify the semi-lethal concentrations of salt stress in Stenotaphrum secundatum using hydroponics to provide a theoretic background for screening salt tolerance of different accessions. The experiment was carried out at 10 concentration gradient treatments, which were 0, 35, 70, 105, 140, 175, 210, 245, 280, and 315 mmol·L-1. To investigate morphological indicators of S. secundatum, plants were treated after 28 days to determine the semi-lethal concentration of NaCl. The results showed that different treatments had significant differences (P<0.05). With the increase in the salt concentration of the treatment, four morphological indexes, which were leaf color, turf quality, stolon length, and dry matter weight increased significantly (P<0.05), whereas leaf firing decreased (P<0.05). Using a linear regression equation, the semi-lethal concentration was found to be 185 mmol·L-1, when the rate of leaf firing was 50%. These results can provide a scientific basis and direction for the later screening of S. secundatum germplasm.