Effects on cold tolerance of M2 of Longmu No.803 alfalfa seed pre-treated with a mixed high-energy particle field

The seeds of Longmu No.803 alfalfa were pre-treated in a mixed high-energy particle field.The effect of M2 on Longmu No.803 alfalfa subjected to low temperature treatment between autumn and winter were studied,including monitoring the leaf for free proline content,SOD activity,LSSC,Chla and Chlb contents after treatment with different radiant dosages.The mixed high-energy particle field significantly(P0.05) increased the cold tolerance of M2 compared with the control.With increasing radiant dosage,the proline content,SOD activity,LSSC,Chla and Chlb contents of M2 were all significantly reduced.The low radiant dosage induced stronger cold tolerance than the high radiant dosage.There were two options involving 145 or 195 Gy of mixed high-energy particle field intensity.