麦田抗性生物型荠菜对苯磺隆的抗性机制研究

为明确抗性生物型荠菜对苯磺隆的抗性机制,分别测定了苯磺隆对抗性和敏感生物型荠菜体内乙酰乳酸合成酶(ALS)、谷胱甘肽-S-转移酶(GSTs)、超氧化物歧化酶(SOD)、过氧化物酶(POD)和过氧化氢酶(CAT)的影响。结果表明:离体条件下,抗性生物型荠菜体内ALS对苯磺隆的敏感性明显降低,苯磺隆对荠菜抗性和敏感生物型ALS的抑制中浓度(I50)分别为0.722 8和0.052 1 μmol/L,抗性与敏感生物型I50的比值为13.87;活体条件下,施用苯磺隆后,抗性和敏感生物型荠菜ALS活性均受到一定程度的抑制,但抗性生物型ALS活性受到抑制后能逐渐恢复,而敏感生物型则不能恢复;经苯磺隆处理后,抗性生物型GSTs相对活力明显高于敏感生物型,而抗性和敏感生物型体内POD、SOD和CAT相对活力无明显差异。研究表明,抗性生物型荠菜体内ALS对苯磺隆敏感性降低是其抗药性产生的原因之一,而GSTs对苯磺隆代谢能力的差异也可能与荠菜对苯磺隆的抗性有关。

Mechanism of resistance to tribenuron-methyl in a resistant biotype of Capsella bursa-pastoris from wheat fields

To ascertain the resistance mechanism of Capsella bursa-pastoris to tribenuron-methyl,the enzyme assays of ALS,GSTs,POD,SOD and CAT in both resistant (R) and susceptible (S) biotypes of C.bursa-pastoris were conducted.The results of in vitro test showed that the sensitivity of ALS to tribenuron-methyl was decreased in the R biotype,the tribenuron-methyl concentration causing 50% inhibition of ALS activity (I50) in R and S biotypes was 0.722 8 and 0.052 1 μmol/L,respectively,and the relative resistance index I50(R)/I50(S)] was 13.87.The results of in vivo experiment indicated that ALS activities were inhibited in both R and S biotypes.The ALS activity of the R biotype could be recovered,while that of the S biotype could not; the GSTs activity of R biotype was obviously higher than that of S biotype; the activities of POD,SOD and CAT in R and S biotypes showed no obvious difference.The results suggested that reduced sensitivity of ALS was one of the resistance mechanisms to tribenuron-methyl in C.buusa-pastoris,and the metabolic ability of GSTs might be also related with the resistance.