Effects of salt-alkali mixed stresses on the seed germination of Halogeton arachnoideus

To study the influence of salt-alkali stresses on seed germination, indoor simulations were performed on Halogeton arachnoideus to investigate the effect of salt-alkali mixed stresses on seed germination, taking salt type and concentration as control factors. Following the sequence NaCl ꞉ Na₂SO₄ ꞉ NaHCO₃ ꞉ Na₂CO₃, mixed in 5 different ratios, we had 5 experimental groups, A－E. Each group was divided into 6 concentrations, for a total of 30 treatments. The results indicate that as salt concentrations increased, the seed germination percentage, germination potential, and germination index of seeds decreased. The seeds that did not germinate in the salt solution were transferred to distilled water, and the seeds of different degrees could resume germination. Via regression analysis, we found the salt tolerance thresholds of A－E to be 0.26, 0.24, 0.23, 0.25, 0.16 mol·L⁻¹ and the salt tolerance limits of 0.65, 0.62, 0.62, 0.60, 0.52 mol·L⁻¹, respectively. Cluster analysis showed that the salt tolerance thresholds of A－E were 0.3, 0.2, 0.3, 0.3 and 0.1 mol·L⁻¹, respectively. The mean value of regression and cluster analysis results showed that the salt tolerance threshold of H. arachnoideus seed germination under mixed salt-alkali stresses was 0.234 mol·L⁻¹, while the salt tolerance limit was 0.602 mol·L⁻¹. The effect of salt concentration on seed germination was larger than that of the salt species. Compared with alkaline salt, H. arachnoideus was more tolerant to a neutral salt environment.