5种化学试剂诱导黄瓜抗霜霉病的研究

目的]比较5种化学试剂诱导黄瓜对霜霉病的抗病性。方法]待黄瓜幼苗长到4叶期时采用水杨酸、草酸、壳聚糖、硝酸钙和磷酸氢二钠诱导处理第2片真叶,7 d后测定第3片真叶防御酶系活性;同时诱导处理后进行接种试验,统计发病情况。结果]5种化学试剂处理在不同程度上均促进黄瓜叶片POD、SOD、PAL和PPO酶活性的升高以及叶片的超微弱发光,降低了黄瓜叶片病情指数。结论]5种试剂处理均诱导叶片产生系统抗性;诱导处理中草酸诱导抗病性的效果最为显著,其余依次是水杨酸、壳聚糖、磷酸氢二钠和硝酸钙。

Induced Resistance of Several Chemicals on Cucumber against Pseudoperonospora cubensis

Objective] The paper was to compare the induced resistance of several chemicals on cucumber against Pseudoperonospora cubensis.Method] When the cucumber seedlings grew to 4-leaf stage,the second true leaf was treated with salicylic acid,oxalatc,chitosan,calcium nitrate and Na2HPO4,the activity of protective enzymes in the third leaf was determined after 7 d.At the same time,inoculation test was also conducted after induced treatment,and the disease condition was counted.Result] These chemical treatments promoted protective enzyme activities(POD,SOD,PAL,PPO) in different degree,improved the ultraweak luminescence,and reduced the disease index of cucumber leaves.Conclusion] Five chemical treatments expressed good effects on induced resistance.Among the treatments,oxalatc had the best induced effect,followed by salicylic acid,chitosan,Na2HPO4 and calcium nitrate.