中文摘要：

对碱性果胶酶诱导黄瓜抗病作用进行了研究。结果表明，菌株吉氏芽孢杆菌S-2（B.gibsonii S-2）和克劳氏芽孢杆菌S-4（B.clausii S-4）发酵生产的碱性果胶酶对黄瓜黄化苗具有诱导抗病作用。在不同酶活的处理中，S-2（200u／m1）和S-4（20u／ml）碱性果胶酶对黄瓜叶和茎上黑星病的病情指数降低最多．其诱导防病效果分别达到73．7％，80．0％和80．6％，86．6％。pH变化对碱性果胶酶的诱导抗病作用影响显著。碱性果胶酶S-2（200u／m1）和S4（20u／ml）在pH8．0时诱导防病效果较好，它们对黄瓜叶和茎上黑星病的诱导防病效果分别达到64．8％，78．5％和75．0％，87．8％。

英文摘要：

Efficiency of induced resistance to cucumber scab by alkaline pectinases was studied. The results indicated that when the alkaline pectinases from Bacillus gibsonii S-2 and Bacillus clausii S-4 were separately sprayed on cucumber seedlings, plant disease resistance was induced. The alkaline pectinase might be used in green food and organic food production. Among the treatments with different alkaline pectinase activity, the alkaline pectinases from both B. gibsonii S-2 with the activity of 200 u/mL and B. clausii S-4 with the activity of 20 u/mL showed the maximum decrease of disease index of scab and efficiency of induced resistance to scab of leaves and stems in cucumber seedlings were 73.7% and 80.0%, 80.6% and 86.6%, respectively, pH variation of alkaline pectinase from B. gibsonii S-2 and B. clausii S-4 showed different effects on efficiency of induced resistance to cucumber scab. At pH 8.0, both the alkaline pectinases from B. gibsonii S-2（200 u/mL ） and B. clausii S-4 （20 u/mL） showed the highest efficiency of induced resistance to cu- cumber scab in the leaves and stems, which were 64.8% and 78.5%, 75.0% and 87.8%, respectively.