Physiological Responses to Exogenous SA and ABA in Alfalfa Varieties under Chilling Stress

Through spraying the appropriate concentration of the exogenous salicylic acid and abscisic acid,to research the physiological responses to exogenous SA and ABA in alfalfa varieties under chilling stress,the results show that the SA,ABA,SA+ABA treatment can improve the dry weight and plant height of alfalfa seedlings significantly,the SA,SA+ABA treatment can improve the contents of soluble sugar of the alfalfa seedlings significantly,the ABA,SA+ABA treatment can improve the proline contents of the alfalfa seedlings significantly,with SA+ABA treatment the most significant of all.Spraying SA and ABA signal material together can greatly improve the enzyme activity of SOD and POD in the alfalfa seedlings,but CAT enzyme activity with no significant difference to contrast.Spraying SA or ABA separately can greatly improve the enzyme activity of POD and CAT in the alfalfa seedlings,but SOD enzyme activity with no significant difference to contrast.The differences of hardiness with the three alfalfa varieties under chilling stress was significant,from high to low,which in turn for:Gongnong No.1Golden EmpressSandeli.