Abstract: [Objective] To investigate the effects of different saline-alkali stresses on seed germination and seedling growth of Bothriochloa ischaemum. [Method] The germination of Bothriochloa ischaemum seeds was observed under the stresses of NaCl, Na₂SO₄, Na₂CO₃ and NaHCO₃, respectively. For each saline-alkali species, the Na⁺ concentrations were set at 10, 30, 90, and 270 mmol/L. To reveal the response of seed germination and seedling growth of Bothriochloa ischaemum to varied saline-alkali stresses, using distilled water treatment as the control, the variations in germination percentage, germination index, and mean germination time of the seeds were assessed, and the changes in vigor index, radicle length, and plumule length of the seedlings were characterized. [Result] The seed germination percentage, germination index and mean germination time, as well as the seedling radicle length and plumule length of Bothriochloa ischaemum were all extremely significantly （P<0.01） affected by different saline-alkali species, Na⁺ concentrations, and their interaction. As the Na⁺ concentrations increased, the seed germination percentage and germination index as well as seedling radicle length and plumule length dropped, but the mean germination time elevated. Different Na⁺ concentrations extremely significantly （P<0.01） affected the seedling vigor index as well, and the seedling vigor index declined as the Na⁺ concentrations increased. Different saline-alkali species had significant （P<0.05） effects on the seedling vigor index, while the interaction between saline-alkali species and Na⁺ concentrations had no significant （P>0.05） effects on the seedling vigor index. The ability of seed germination and seedling growth declined as the concentrations of Na⁺ increased, and it was higher under NaCl and Na₂SO₄ stresses than under Na₂CO₃ and NaHCO₃ stresses. [Conclusion] The seed germination and seedling growth of Bothriochloa ischaemum exhibited tolerance to the stresses of NaCl, Na₂SO₄, Na₂CO₃, and NaHCO₃ with a Na⁺ concentration of 10 mmol/L. Its tolerance to neutral salt was higher than that to alkaline salt. The effects of saline-alkali stresses on the radicle growth of Bothriochloa ischaemum seedling were greater than that on the plumule growth.

Key words: Bothriochloa ischaemum, saline-alkali stress, seed vigor, seed germination, seedling growth