Comprehensive evaluation of salt tolerance of three forage seed varieties during germination

Three native grasses of Qinghai Province, Elymus nutans, E. breviaristatus and E. sibiricus, were taken as research objects and NaCl and Na₂SO₄ salt solutions were used for stress treatment. The germination traits of three kinds of seeds were analyzed and determined under the salt stress, and the salt tolerance was evaluated through the comparative analysis of the differences between each indexes. The results showed that with increasing salt concentration, the germination percentage, germination potential, germination index, and vigor index of each kind of seed decreased to different degrees, and the relative salt damage rate gradually increased. Radicle length and germ length decreased with increasing salt concentration, while the bud to root ratio first increased then decreased, indicating that salt stress was more toxic to radicle than to germ. The salt tolerance of three kinds of herbage was comprehensively evaluated by principal component weighting and membership function methods, revealing that Elymus nutans exhibited the strongest NaCl salt stress tolerance, and E. breviaristatus exhibited the most stability in response to two kinds of salt stress, suggesting it as a candidate herbage for planting in saline-alkali land.