Effects of Nickel Stress on Seed Germination and Growth Physiology of Medicago sativa L.

Taking alfalfa as test materials, the hydroponic experiment method was used, the effects of different nickel concentrations stress(0,1,5,10,50,100,200 mg·L^-1) on alfalfa seeds and seedlings growth physiological indicators were studied, in order to understand the alfalfa growth physiological changes under heavy metal stress, and provide a reference for alfalfa applied to soil restoration.The results showed that seed germination of alfalfa was inhibited and seed vigor index under stress decreased significantly higher than 5 mg·L^-1.At the seedling stage（10 days）,the contents of chlorophyll and protein decreased, the contents of reactive oxygen and membrane lipid peroxidation products（malondialdehyde） increased, the activities of superoxide dismutase and peroxidase, the contents of proline and soluble sugar increased, and the absorption of nickel to the seedlings increased multiple, which affected the normal growth and metabolism of the seedlings.Test showed that alfalfa could maintain the normal growth metabolic level through a series of oxidative stress responses under low concentration of nickel stress and showed certain nickel resistance.