营养胁迫及农药胁迫等逆境在农业田间生产中十分常见.为明确不同营养胁迫条件下,常用杀虫剂使用对小麦苯丙氨酸解氨酶(PAL)的影响,研究了3种质量浓度的吡虫啉、灭多威、氧乐果分别处理清水及营养液中培养的小麦苗后5d内,对小麦苗苯丙氨酸解氨酶活性的影响.结果表明,35mg/L吡虫啉处理营养液组及清水组小麦苗后6h时,小麦苗PAL均受到抑制,活性显著降低;在处理后12h时,营养液组小麦PAL活性与对照相比,显著升高了37.8%,而清水培养的小麦苗PAL未出现显著升高;100,200,400mg/L灭多威处理对2组小麦苗中PAL活性的影响与吡虫啉处理类似.氧乐果处理后6h,营养液组小麦苗PAL活性比对照显著升高了107.8%,在处理后24h时,营养液组小麦PAL活性又显著降低,而后变化不再显著;而清水组小麦苗PAL活性在氧乐果处理后12h及48h时,活性显著降低,在处理后5d内,均无显著升高阶段.可见,杀虫剂对小麦苗中PAL活性的影响与药剂本身的性质有关,还具有一定的剂量效应与时间效应.营养状况对小麦苗的PAL防御响应也会产生一定的影响.清水培养组小麦与营养液培养组小麦相比,在药剂胁迫下,PAL活性在营养物质充足条件下的防御响应更为显著,并迅速恢复为不受影响的正常状态.

The pesticide stress and the nutritional stress are two common adverse environmental stresses in the agricultural practice. As one kind of external stress factors, the pesticide application would affect the physiological and biochemical process of plants, such as the photosynthesis, the nutrient substance and the secondary metabolism. The nutrient substance would also affect the physiological and the biochemical processes of plants. In order to fight against the adversity, the plants would make a manifold recovery. The defense related enzymes of the plants play an important role in the fight against the adversity. The paper focuses on the effects of imidacloprid, methomyl and omethoate on the Phenylanlanine Ammonialyase(PAL) in wheat seedlings under the nutrition stress. The activities of PAL in wheat seedlings were examined after treatment by three kinds of insecticides for 5 days. It is shown that the activity of PAL in wheat seedlings cultured in the nutrient solution experiences a significant descending-raising process after being treated by 35mg/L imidacloprid. The activity of PAL in wheat seedlings cultured in water does not experience a significant raising process. The studies involving methomyl reveal similar results as with imidacloprid. After being treated by omethoate, the activities of PAL in wheat seedlings with the two treatments saw a significant difference. After being treated by omethoate for 6h, the activity of PAL in wheat seedlings cultured in nutritious substances significantly increased by 107.8%, after being treated for 24h, the activity of PAL saw a significantly decrease . Therefore, the activities of PAL in wheat seedlings might be affected by the presence of nutritious substances. The activities of PAL in wheat seedlings were influenced by the types of insecticides, as well as the concentration of insecticides and the treatment duration. Compared with wheat seedlings cultured in water, the activity of PAL of wheat seedlings cultured in a nutrient solution saw a more significant defense response.