摘要： 黄瓜幼苗经水杨酸处理后，POD、PPO、PAL3种酶活性均有不同程度的变化，与对照相比，POD活性在处理后24h有明显提高，以后一直呈上升趋势，至144h后较对提高1930%。PPO活性变化相对较小，酶活性的明显提高在处理48h以后，处理后144h时较对照提高617%。PAL在处理后72h时出现一个小的酶活性峰，较对照提高176%，而后下降，120h出现第2个活性峰，较对照提高308%。处理后4d接种霜霉病菌，调查结果表明：第1真叶处理较对照病情指数降低89%，第2真叶处理较对照降低221%。

关键词: 水杨酸, 过氧化物酶, 多酚氧化酶, 苯丙氨酸解氨酶, 黄瓜霜霉病, 诱导抗性

Abstract: Cucumber seedlings were treated with SA at two-leave stage with one real leave expanded and the other real leave unexpanded.The ac tivity of POD,PPO and PAL changed in different level after treatment.The activity of POD changed obviously at 24h after treatment,and increased steadily,till 144h after treatment it increased 193% as compared with control.However the changes of PPO activity were less than that of POD.The activity of PPO increased by 61.7% 144h after treatment.The PAL a ctivity reached a little peak 72h after treatment and then declined,another peak appeared in 120h after treatment.Inoculation with Pseudoperonospora cub ensis 4d after treatment,the results show that the disease index of the fi rst and the second real leaves were reduced by 8.9% and 22.1% respectively.

Key words: Salicylic acid, POD, PPO, PAL, Cucumber downy mildew, Induced resistance

中图分类号: 

• S642.201