Effects of melatonin on growth and physiology of Medicago sativa seedlings under salt-alkali stress

ZHANG Yanan; ZHU Chenning; WANG Jun; WANG Zhucheng

doi:10.13557/j.cnki.issn1002-2813.2025.05.017

Abstract：The experiment aims to screen for the most suitable melatonin(MT)soaking concentration that promotes the growth and physiological effects of Medicago sativa under salt-alkali stress.Using Medicago sativa Suntory and Gannong No.3 as experimental materials,seeds were soaked with MT solution of 0(T1 group),50(T2 group),100(T3 group),150(T4 group),200 μmol/L(T5 group),and seedlings were subjected to salt-alkali stress,while seeds were soaked with distilled water only without salt-alkali stress in CK group,with three replicates per group.The physiological indicators such as root length,plant height,and malondialdehyde(MDA),soluble sugart,and proline(Pro)content of Medicago sativa seedlings under alt-alkali stress were measured.The results showed that the root length,plant height,dry weight,and fresh weight of Medicago sativa seedlings in T4 group were significantly lower than those in CK group(P<0.05),but significantly higher than those in T1 group(P<0.05).The MDA content in T4 group was significantly decreased compared with that in T1 group(P<0.05),while the activities of superoxide dismutase(SOD),peroxidase(POD)and catalase activity(CAT)in T4 group were significantly higher than those in T1 group(P<0.05).The concentrations of soluble sugar and Pro in alfalfa seedlings in T3 group were significantly higher than those in CK group(P<0.05).The results of membership function evaluation showed that the salt-alkali tolerance of Suntory and Gannong No.3 was ranked as CK group>T4 group>T3 group>T2 group>T5 group>T1 group,indicating that 150 μmol/L MT solution had the best effect on salt-alkali stress relief.The study indicates that Gannong No.3 is more sensitive to environmental changes,showing a stronger response to saline-alkali stress,while Suntory showed a stronger resistance.