The Induction Effect of Jasmonic Acid on Alfalfa Disease Resistance

To explore the induced effect of the exogenous jasmonic acid(JA)on induced resistance against alfalfa diseases,the disease indexes of the leaf spot disease and black stem disease on alfalfa were measured by treating with smear inoculation at different concentrations.Activities of related defense enzymes such as peroxidase(POD),polyphenol oxidase(PPO)and phenylalanine ammonia lyase(PAL)were also analyzed.The results showed that the disease indexes of the leaf spot disease and black stem disease can be lightened by daubing leaf surface with 1mg/mL JA,two disease incidence and disease index were significantly lower than the control.The activity of three kind's defense enzyme of POD,PPO and PAL increased in varying degrees by JA treatment.These results indicated that exogenous JA induced disease resistance against alfalfa diseases which related to the increase of activities of defense enzymes caused by JA.