3种常用杀虫剂胁迫对小麦防御相关酶活性的影响

Effects of three kinds of pesticides on activities of defense-related enzymes in wheat seedlings

为明确常用杀虫剂对小麦防御性的影响,考察了吡虫啉、灭多威和氧乐果处理对小麦苗3种防御相关酶活性的影响。分别使用杀虫剂的田间推荐浓度、高于和低于其推荐浓度1倍的质量浓度3个处理,考察了吡虫啉、灭多威和氧乐果营养液内吸处理小麦苗后5d内,小麦苗中苯丙氨酸解氨酶(PAL)、谷胱甘肽硫转移酶(GSTs)和脂氧合酶(LOX)活性的变化。结果表明:17.5和35.0mg/L吡虫啉处理小麦苗后6h时,小麦苗中PAL均受到抑制,活性显著降低,处理后12h时,PAL活性与对照相比显著上升,分别上升了38.9%和40.0%;100、200和400mg/L灭多威处理小麦苗后12h时,小麦苗中PAL活性显著升高。250、500和1 000mg/L氧乐果处理小麦苗后24h内,小麦苗中PAL活性呈现出先升高再降低的动态过程。而500和1 000mg/L氧乐果处理小麦苗后48h内,小麦苗中GSTs活性呈现出先降低再升高的动态过程。在3种杀虫药剂的胁迫下,小麦苗PAL、GSTs及LOX活性均发生了随着时间而变化的波动,随着处理后时间的继续延长,最后小麦苗3种防御酶的活性又恢复至不受影响的正常状态。一定浓度的吡虫啉、灭多威和氧乐果处理小麦苗,会对小麦苗中PAL、GSTs和LOX的活性及其相关防御性产生一定影响。3种杀虫剂对小麦苗中PAL、GSTs和LOX活性的影响,不仅与杀虫药剂本身的性质有关,还具有一定的剂量效应与时间效应。

Pesticides affect the physiology and biochemistry of plants,such as photosynthesis,nutrient substance and so on. In order to explore the effects of pesticides on the defense of wheat to pests and pathogen, the activities changes of the three defense-related enzymes of phenylanlanine ammonialyase （PAL）, glutathione S-transferases （GSTs） and lipoxygenase （LOX）,were examined in wheat seedlings during 5 days after treated with imidacloprid, methomyl and omethoate respectively. The results showed that the activities of PAL decreased significantly at 6 h after treatment with 17.5 and 35.0 mg/L imidacloprid respectively,while increased by 38.9% and 40.0% respectively at 12 h after the treatment compared to the untreated control. When treated with 100,200 and 400 mg/L of methomyl, the activities of PAL in wheat seedlings increased markedly at 12 h. During 24 h after treated with 250,500 and 1 000 mg/L omethoate, the activities of PAL experienced a significant raising-descending process. In contrast, the activities of GSTs had a significant descending-raising process during 48 h after treated by 500 and 1 000 mg/L omethoate. Under the stresses of three pesticides, the activities of PAL, GSTs and LOX in wheat seedlings showed variation with time. They finally returned to normal conditions. The activities of PAL, GSTs and LOX in wheat seedlings treated with insecticides depended not only on the types of insecticides, but the concentration of insecticides and the duration time of treatment as well.