不同处理及pH变化对果胶酶诱导抗病性的影响

从不同处理方法、酶液pH变化等方面对果胶酶诱导黄瓜抗黑星病效能的影响进行了研究。结果表明，在果胶酶的4种不同处理试验中，以全株表面喷雾法处理的黄瓜黄化子叶黑星病的病情指数降低最多，浓度100和200U／ml的诱导防病效果分别为56．34％和64．13％；下胚轴注射、灌根和漫种等3种处理方法的诱导抗病效果均不显著。经果胶酶诱导处理的黄瓜绿苗叶片病情明显降低，而处理叶上部的未处理叶片发病情况与相应对照差别不大。该结果表明，果胶酶诱导黄瓜绿苗抗黑星病的作用属于局部诱导。果胶酶处理次数的增加可增强其诱导抗病效果，并延长诱导抗病时间。酶液pH变化对果胶酶的诱导抗病作用影响显著，pH5．5时，2个浓度的诱导效果最好，分别为51．87％和66．42％。

Effect of Application Methods and pH Values on Induced Resistance of Pectinases Extract against Scab Disease of Cucumber

Influence of different treatment methods and pH variation of pectinases extract of Penicillium oxalicum on its efficiency of induced resistance to scab caused by Cladosporium cucumerinum in cucumber plants was studied.Among these 4 treatment methods,spray application showed the maximum decrease of disease index of scab and the induced efficiency of two concentrations of pectinases(100 and 200 U/ml) were 56.34% and 64.13%,respectively.Other methods,including hypocotyls injection,root soakage and seed treatment had less induced efficiency. The disease index decreased in pectinases treated leaves,while no difference in disease index was observed between untreated leaves and control leaves.The result indicated the induced efficiency against the disease mainly attributed to local resistance.Repeated applications of pectinases extract enhanced induced efficiency and prolonged the duration of control of the disease.pH variation of pectinases extract showed different effect on induced resistance to cucumber scab.At pH5.5,cucumber plants expressed the highest resistance with induced efficiency of 51.87% and 66.42% respectively at the two concentrations.