To investigate the growth and metabolic adaptability of alfalfa （Medicago sativa L.） under saline-alkali soil conditions， this experiment used ‘Zhongmu No.3’ alfalfa cuttings as the test material. Set up neutral salt stress （NaCl+Na₂SO₄） and alkaline salt stress （Na₂CO₃+NaHCO₃） treatments， with three gradient levels for each： light （0.3% soil salinity）， moderate （0.6%）， and severe （0.9%）. After 15 days of stress， the growth physiological indicators of plant leaves and roots were measured. The results showed that alfalfa exhibited significant growth and physiological responses under saline-alkali stress. With increasing stress intensity， growth parameters under neutral salt treatment reached the lowest level under severe stress treatment （NS）， whereas alkaline salt treatment exhibited a gradual decrease in growth parameters as treatment intensity escalated. The sodium ion （Na⁺） content in the leaves and roots significantly increased under different treatments. The content of malondialdehyde （MDA） in the leaves significantly rose under moderate （NM） and NS neutral salt stress treatments； meanwhile， the MDA content in both roots and leaves significantly increased under various alkaline salt stresses. The proline （Pro） content in the roots significantly increased under different stresses， while the activity of superoxide dismutase （SOD） first increased and then decreased as the stress level rose. This study reveals the growth and metabolic adaptation mechanisms of alfalfa under saline-alkali stress， providing research references for the breeding of salt-tolerant varieties.

Alfalfa  /  Saline-alkali stress  /  Growth traits  /  Physiological response