不同小麦品种对双氟磺草胺的耐药性差异及机理

室内采用平皿法和酶活力测定法探讨了不同小麦品种对双氟磺草胺的耐药性差异及其机理。结果表明,不同小麦品种根对双氟磺草胺的耐药性差异较大,其中济宁13对该药剂最为敏感,IC50值仅为0.221 2 μg/mL,烟农15、枣20-28、济南17与之相当(耐药性倍数为1.09~1.99),泰山9818、山农6号和潍麦8号耐药性较强(耐药性倍数为10.33~13.92)。酶活力测定结果表明:虽然耐药型品种潍麦8号和敏感型品种济南17对双氟磺草胺的耐药性差异显著,但其靶标酶乙酰乳酸合成酶(ALS)在离体条件下对该药剂的敏感性却无显著差异;在活体条件下,二者ALS活力均可很快恢复,其中潍麦8号恢复较快。经双氟磺草胺处理后,与济南17相比,潍麦8号的代谢酶谷胱甘肽- S -转移酶(GSTs)相对活力变化幅度较大且反应时间较短,在第2 d即可达到峰值1.460,而济南17在第3 d才达到峰值1.398。研究表明,不同小麦品种对双氟磺草胺的耐药性存在差异 的原因之一可能是由于GSTs对双氟磺草胺的代谢差异,而与靶标酶ALS对药剂的敏感程度无关。

Difference and mechanism of tolerance of various wheat varieties to florasulam

The difference and mechanism of tolerance of various wheat varieties to florasulam were measured by dish dipping and enzyme assay in laboratory.The results demonstrated that the roots of various wheat varieties showed different tolerance to florasulam,and Ji’ning 13 was the most sensitive variety(IC50 value 0.221 2 μg/mL).The tolerance of Yannong 15,Zao 20-28 and Ji’nan 17 were similar to that of Ji’ning 13(with the tolerance ratio 1.09-1.99),while Taishan 9818,Shannong 6 and Weimai 8 showed relatively high tolerance(with the tolerance ratio 10.33-13.92).Weimai 8 and Ji’nan 17 were chosen for enzyme assay.The results showed that the sensitivity of Weimai 8 and Ji’nan 17’s ALS in vitro to florasulam was not significantly different,even though the difference in tolerance between the two varieties was significant.The in vivo ALS activity of the two varieties could recover rapidly,and the recovery of Weimai 8 was faster than that of Ji’nan 17.The GSTs activity of Weimai 8 showed a rapider and stronger response than that of Ji’nan 17 after being treated by florasulam.The relative GSTs activity of Weimai 8 reached the peak value 1.460 in the 2nd day but that of Ji’nan 17 reached the peak value 1.398 in the 3rd day.The results of present study suggested that the mechanism of various wheat varieties showed different tolerance to florasulam may not related with the sensitivity of ALS,but with the enhancement of wheat’s GSTs activity.