Inducing Effects of BTH Treatment on Melon Resistance to Powdery Mildew at Different Growing Stages

Inducing effects of BTH spaying on resistance to powdery mildew( Erysiphe cucurbitacearum)at 3 stages of melon(Cucumis melo L.)plants were studied, taking melons of seedling, tendril and young fruit stages as experiment materials. The results showed that 0.25 mmol·mL-1 BTH had significanty higher inducing effect on melons at seedling and tendril stages than at the young fruit stage. But inducing effects are not significantly different between melon in tendril and seedling stages. After 0.25 mmol·mL-1 BTH treatment, the amplification of GLU activity in melon leaf-blades at seedling stage is the largest, the next is at tendril stage and the lowest is at young fruit stage. The climax of PAL activity in leaf-blades is postponed along with the increase of plant ages, no matter it is an induced+inoculation plant or a pure inoculation plant.