【摘要】 【目的】探究外源水杨酸对燕麦（Avena sativa）抗叶斑病的诱导效应及诱导抗病机理。【方法】以牧乐思燕麦品种为试验材料，叶面喷施不同浓度水杨酸（0、0.1、0.25、0.5、1和5 mmol/L）后接种病原菌徳氏霉（Drechslera avenae），以未接种病原菌为对照，接种9 d后统计病情指数和采集叶片测定抗氧化系统和苯丙氨酸解氨酶活性等生理指标，以不同浓度的水杨酸作为诱抗剂测定对德氏霉病原菌的抑制率。【结果】外源水杨酸对病原菌的生长没有抑制作用；接种德氏霉病原菌后明显抑制燕麦生长，喷施不同浓度水杨酸可诱导燕麦抵抗德氏霉叶斑病，其中1 mmol/L水杨酸处理下病情指数、超氧阴离子产生速率、H₂O₂含量和MDA含量最低，分别低于只接种德氏霉病原菌处理47.85%、45.45%、29.29%和47.85%，叶绿素含量、SOD、POD、CAT和APX活性最高，分别高于只接种德氏霉病原菌处理24.78%、60.31%、76.22%、60.15%和19.35%;0.25 mmol/L水杨酸处理下PAL活性最高，高于只接种德氏霉病原菌处理73.12%;0.5 mmol/L水杨酸处理下总酚和类黄酮含量最高，分别高于只接种德氏霉病原菌处理45.76%和43.95%。【结论】综合各项指标结果，各浓度诱导燕麦抗叶斑病处理下1.00 mmol/L水杨酸处理下表现最优。外源水杨酸能够诱导燕麦对叶斑病的抗性，降低病情指数，增加叶绿素含量，并且能提高抗氧化酶活性，使体内活性氧达到稳态水平，还能提高苯丙烷代谢途径中的PAL活性，有利于提高次生代谢物合成，提高自我保护性。更多还原

【Abstract】 【Objective】 The study aims to explore the induction effect of exogenous salicylic acid on the resistance of oat（Avena sativa） to leaf spot disease and its induced resistance mechanism.【Method】 Using the Mulesi oat variety as the experimental material,different concentrations of Salicylic acid（0,0.1,0.25,0.5,1,and 5 mmol/L） were sprayed on the leaves and inoculated with the pathogen Drechslera avenae.The disease index and physiological indicators such as antioxidant system and phenylalanine ammonia-lyase activity were measured after 9 days of inoculation with the pathogen as the control.Different concentrations of salicylic acid were also used as inducers to determine the inhibition rate against Drechslera avenae.【Result】 Exogenous salicylic acid had no inhibitory effect on the growth of pathogenic bacteria.Leaf spot disease significantly inhibited oat growth,and spraying different concentrations of salicylic acid could induce oat resistance to Drechslera avenaeleaf spot disease.Among them,the disease index,superoxide anion production rate,H₂O₂ content,and MDA content were the lowest under the treatment of 1 mmol/L Salicylic acid,which were 47.85%,45.45%,29.29%,and 47.85% lower than the treatment only inoculated with Drechslera avenae.Chlorophyll content,SOD,POD,CAT,and APX activity were the highest,and 24.78% higher than the treatment only inoculated with Drechslera avenae 60.31%,76.22%,60.15%,and 19.35%.The highest PAL activity was observed in the treatment with 0.25 mmol/L Salicylic acid,which was 73.12% higher than that in the treatment only inoculated with Drechslera avenae.The total phenolic and flavonoid contents were the highest under the treatment of 0.5 mmol/L Salicylic acid,which were 45.76% and 43.95% higher than those under the treatment of only inoculating Drechslera avenae,respectively.【Conclusion】 Based on the comprehensive results of various indicators,the best performance was observed under the treatment of 1 mmol/L Salicylic acid induced resistance to leaf spot disease in oats at different concentrations.Exogenous Salicylic acid could induce oat to reduce disease index,an increase in chlorophyll content,and an increase in antioxidant enzyme activity,leading to a steady state of reactive oxygen species in the body.It could also increase PAL activity in the phenylpropanoid metabolism pathway,which was beneficial for improving secondary metabolite synthesis and self-protection.This study provided a new approach for the prevention and control of oat leaf spot disease.更多还原