茉莉酸对苜蓿抗病性的诱导作用

The Induction Effect of Jasmonic Acid on Alfalfa Disease Resistance

为探索外源茉莉酸(JA)对苜蓿抗病性的诱导效应,采用涂抹接种法测定了JA对苜蓿幼苗的匍柄霉叶斑病、春季黑茎病病情指数及叶片过氧化物酶(POD)、多酚氧化酶(PPO)和苯丙氨酸解氨酶(PAL)等相关防御酶活性的影响。经1mg/mL茉莉酸涂抹叶面可减轻苜蓿匍柄霉叶斑病和春季黑茎病的发生,两病害的发病率和病情指数均明显低于对照;苜蓿叶片中POD、PPO和PAL三种防御酶的活性均有不同程度提高,表明外源JA处理对苜蓿抗病性具有诱导作用。

To explore the induced effect of the exogenous jasmonic acid （JA） on induced resistance against al- falfa diseases, the disease indexes of the leaf spot disease and black stem disease on alfalfa were measured by trea- ting 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 ean be lightened by daubing leaf surface with lmg/mL JA, two disease incidence and disease index were significantly lower than the control. The ac- tivity 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.