乳果糖对黄瓜枯萎病防效及其诱导抗性的作用

测试乳果糖对黄瓜枯萎病的防治作用,并通过黄瓜相关抗性酶活性的影响,明确乳果糖对黄瓜枯萎病的防治效果及初步作用机制。采用生长速率法测定乳果糖对黄瓜枯萎病菌的抑制率;采用胚根接种法、灌根接种法进行盆栽防效测试;相关抗性酶活性测试采用分光光度法。1 mg/L乳果糖的盆栽防效最好,胚根期浸种和子叶期喷雾处理的防治效果分别为43.87%和41.97%,其次是0.1 mg/L乳果糖的盆栽防效,分别为39.62%和37.21%,而离体抑菌活性测试结果显示乳果糖对黄瓜枯萎病菌无杀菌活性。对黄瓜防御反应酶系过氧化物酶(POD)、过氧化氢酶(CAT)、多酚氧化酶(PPO)、苯丙氨酸解氨酶(PAL)活性进行测试,结果表明乳果糖处理后黄瓜内各防御酶系均比对照高,尤其1 mg/L乳果糖胚根浸种和子叶期喷雾处理黄瓜PAL比对照分别提高了97.5%和92.4%。综上,乳果糖对黄瓜的诱导抗性作用是防治黄瓜枯萎病的主要机制,并可作为新型药剂用于农业植物病害防治中,具有较大开发潜力。

Lactulose: Control Effect on Cucumber Fusarium Wilt and Its Induced Resistance in Cucumber

To explore the control effect and elementary mechanism of lactulose on cucumber Fusarium wilt, samples treated with different concentrations of lactulose and activity of related resistance enzymes were tested on cucumber. Inhibition rate of lactulose on Fusarium oxysporum f. sp. cucumerinum was determined by the growth rate method, the control effect test was carried out with radicle inoculation method and root inoculation method in potted cultivation, and the activity of related resistance enzymes were assayed by spectrophotometry. 1 mg/L lactulose had the best control effect in the concentration gradient test, and the control effect was 43.87% and 41.97% through seed soaking at radicle stage and spray at cotyledon stage, respectively, followed by the control effect of 0.1 mg/L lactulose, which was 39.62% and 37.21%, respectively. However, in vitro activity against Fusarium oxysporum f. sp. cucumerinum test showed that lactulose had no activity. The activity test of peroxidase(POD), polyphenol oxidase(PPO), catalase(CAT) and phenylalanine ammonia lyase(PAL) in cucumber showed that lactulose treated samples expressed higher level of activity than that of control, especially PAL activity of seed soaking at radicle stage and spray at cotyledon stage with 1 mg/L lactulose increased by 97.5% and 92.4%, respectively. In summary, the main mechanism of controlling cucumber Fusarium wilt is the induced resistance of cucumber by lactulose, which can be used as a new kind of biological pesticide in agricultural plant disease prevention and has great potential for development.