Seed germination and early seedling growth of six wetland plant species in saline-alkaline environment

This study focused on the effect of saline and alkaline stress on six typical wetland plant species during seed germination and early seedling growth stages. Based on the indicators of germination, seedling growth and ionic absorption in seedlings, relatively saline and alkaline tolerant plant species were selected and tolerance mechanism was discussed. Results showed that the existence of saline and alkaline stress inhibited the capacity of germination and early seedling growth of most tested plant species to varying degrees, therein effects of saline-alkaline stress were greater than saline stress. Based on the results of principal component analysis (PCA), germination percentage, K⁺ content, plant height, Na⁺ content and Na⁺/K⁺ ratios can be selected as representative indicators for saline and alkaline tolerance evaluation during seed germination and early seedling growth stages. Among tested species, Juncus effusus and Vetiveria zizanioides exhibited relatively higher saline and alkaline tolerant capacity during their seed germination and early seedling growth. Additionally, both species increase K⁺ accumulation and retain lower Na⁺/K⁺ ratios, which might be their tolerance mechanisms at ion level. In conclusion, V. zizaniodes and J. effusus were recommended as potential plant species for restoring degraded saline-alkaline wetlands and/or establishing constructed wetlands for treating saline wastewater.