乙烯产生的抑制与氟乐灵诱导棉苗对枯萎病的抗性有关(英文)

The Correlation Between Inhibition of Ethylene Production and Trifluralin-induced Resistance of Cotton Seedlings Against Fusarium oxysporum f.sp.vasinfectum

氟乐灵处理可诱发棉苗产生对枯萎病的诱导抗性，表现为推迟显症，降低发病率和病情指数。经1．0－4．0μg／g的氟乐灵处理后，棉苗受枯萎病菌侵染时其叶片和根茎部组织中乙烯的产生量明显下降（表1），而且病菌侵染后氟乐灵处理棉苗中乙烯产生的抑制与其发病率和病情指数的下降呈正相关（图1）。经氟乐灵处理的棉苗受病菌侵染后喷以138．4μmol/L的乙烯利可同时提高其组织中乙烯的产生量以及发病率和病情指数（图2），而未经氟乐灵处理的棉苗受病菌侵染后喷以乙烯合成抑制剂──2，4-二硝基苯酚和乙烯作用抑制剂──硫代硫酸银则明显降低发病率和病情指数（表2）。由此认为，乙烯产生的抑制可能与氟乐灵诱发棉苗产生对枯萎病的诱导抗性有关。

Trifluralin treatment increased theresistance of cotton seedlings to Fusarium wiltcaused by F. oxysporum f. sp. vasinfectum ,with delayed appearance of wilt symptoms andreduced disease incidence and disease seventyindex (DSI ). Ethylene production in bothleaves and steins/roots was markedly inhibitedby pretreatment with trifluralin at 1. 0 ~ 4. 0μg/g of soil after infection by the pathogen .The suppression of ethylene production in diseased seedlings by trifluralin was positively related to the reduction of disease incidence andDSI. Spraying the trifluralin-treated cottonseedlings with ethephon 138. 4 μmol/L afterinoculation increased both ethylene production and disease incidence and DSI. In contrast,foliar spray of seedlings grown in herbicide -freesoils with ethylene biosynthesis inhibitor (2, 4dinitrophenol ) and ethylene action inhibitor(silver thiosuifate) after inoculation resulted inthe reduction of disease incidence and DSI.These results suggested that suppression ofethylene production may be involved in trifluralin-induced resistance of cotton seedlings toFusarium wilt.