[目的]测定直播水稻田千金子(Leptochloa chinensis(L)Nees.)对氰氟草酯的抗药性水平及氰氟草酯对千金子代谢酶和抗氧化酶的影响,为千金子的科学防治和抗性治理提供理论参考.[方法]采用整株植物测定法测定湖南省部分地区10个直播稻田千金子种群对氰氟草酯的抗药性水平,并比较千金子抗性和敏感种群间谷胱甘肽S-转移酶(GSTs)、超氧化物歧化酶(SOD)、过氧化物酶(POD)及过氧化氢酶(CAT)活力的差异.[结果]以湄江千金子种群为敏感品系,其他千金子种群对氰氟草酯的抗性指数为1.2~11.0,其中衡阳茶山坳种群的抗性指数最高,达11.0.经75.000 g/ha氰氟草酯处理2 d后,抗性种群GSTs活力急剧上升,于药后3 d达最高值,之后急剧下降,5 d后趋于平缓;药剂处理1 d后,敏感种群GSTs活力急剧上升,在药后2 d达最高值,之后下降,敏感种群GSTs活力在3~7 d均低于同期抗性种群.经药剂处理后,抗性种群与敏感种群SOD、POD及CAT活力变化趋势基本一致,但抗性种群始终高于同期敏感种群.[结论]10个千金子种群中衡阳茶山坳种群对氰氟草酯的相对抗性水平最高,处于中等抗药性水平.千金子抗性种群对氰氟草酯产生抗性可能与GSTs、SOD、POD和CAT活力增强有关.%[Objective]In the present study,resistance of Leptochloa chinensis(L) Nees. to cyhalofop-butyl in rice field of direct seeding and influence of cyhalofop-butyl on L. chinensis(L) Nees. metabolic enzyme and antioxidase were studied, in order to provide reference for control and resistance management of L. chinensis(L) Nees. [Method]Using whole-plant assay method, resistance levels of different L. chinensis(L) Nees. populations from ten rice fileds of direct seeding to cyhalofop-butyl were detected. The differences between resistant and susceptible L. chinensis(L) Nees. popula-tions in activities of Glutathione s-transferase(GSTs), superoxide dismutase(SOD), peroxidase(POD) and catalase(CAT) were analyzed. [Result]Results showed that Meijiang population was identified as susceptible population, the resistance in-dex of other populations to cyhalofop-butyl was 1.2-11.0, and the highest resistance index was 11.0, which was found in Chashan'ao town, Hengyang. The activity of GSTs in resistant population increased sharply after 2 days of 75.000 g/ha cyhalofop-butyl treatment, reached the highest value after day 3, then decreased rapidly and became steady after day 5. One day after the treatment, the activity of GSTs in susceptible population increased sharply and reached the maximum on day 2, and then declined. The activity of GSTs in the susceptible population was lower than that of the resistant population during day 3-7. The variation trend of SOD, POD and CAT activities in resistant and susceptible populations was similar, but the values of resistant population was significantly higher than those of susceptible population. [Conclusion]Among ten L. chinensis(L) Nees. populations, the resistance level of Chashan'ao population to cyhalofop-butyl was the highest, which is at a moderate level. The resistance of the resistant L. chinensis(L) Nees. population to cyhalofop-butyl may be related to the enhancement of GSTs, SOD, POD and CAT activities.
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