麦田抗性生物型猪殃殃对苯磺隆的抗性机制

为探讨猪殃殃Galium aparine抗药性生物型(R)对苯磺隆的抗性机制,测定了苯磺隆对猪殃殃抗性、敏感(S)生物型体内靶标酶 、代谢酶 及抗氧化酶 影响的差异。离体试验结果表明,苯磺隆对R、S生物型猪殃殃ALS的抑制中量(IC50)分别为0.682、0.718 μg/L(有效剂量),R、S生物型猪殃殃ALS对苯磺隆的敏感性不存在差异。活体试验结果表明,苯磺隆茎叶喷雾处理后,R、S生物型ALS活力均表现为先上升,但S生物型上升幅度小,且随后快速下降,第3 d即回落至对照之下,并维持在低于对照的水平,而R生物型ALS活力在第2 d可达对照的4.10倍,第5 d 基本回落至对照水平,之后基本维持在对照水平;R生物型GSTs活力在第1 d即开始上升,最高可达对照的 2.40 倍,而S生物型则表现为先下降,然后小幅回升,最高为对照的1.61倍,两者在10 d左右均回落至对照水平;R生物型SOD活力与对照基本相同,而S生物型虽略有下降,但R、S间不存在显著差异;两者POD活力虽均有大幅提高,但亦不存在显著差异。结果表明,低水平抗药性生物型猪殃殃对苯磺隆产生抗性的原因可能是ALS过量表达及GSTs对苯磺隆的代谢作用加强,而不是由于ALS的敏感性下降,同时POD、SOD在减轻药害中也具有一定作用。

Mechanism of Resistance to Tribenuron-methyl in a Resistant Biotype of Galium aparine

In order to study the mechanism of the biotype of Galium aparine resistant to tribenuron-methyl,the differences on ALS,GSTs,SOD and POD of the resistant (R) and susceptible (S) biotypes to tribenuron-methyl were preliminarily determined.There was no significant difference between the sensitivity of ALS in vitro from the R and S biotypes to tribenuron-methyl,with the IC50,0.682 and 0.718 μg(a.i.)/L,respectively.The ALS activity in vivo of both R and S biotypes increased at the first 2 days after application of tribenuron-methyl,however,the ALS activity in vivo of S biotype increased much less and declined much more quickly,less than the control value 3 days after treatment and lasted out,while that of R biotype is 4.10 times of the control,and declined slowly to the control value 5 days later and kept on.Meanwhile,the GSTs activity of R biotype increased immediately, with the peak value 2.40 times of the contemporary control,while that of S biotype declined at first and then increased,with peak value 1.61 times.Both of them came down to the control value 10 days later.The SOD activity of R biotype maintained the control level,while that of S biotype declined a little,but no significant difference existed.The POD activity of both biotypes increased greatly,but no significant difference existed either.The results indicate that the low level resistance to tribenuron-methyl in the biotype of Galium aparine from Xuchang,Henan Province,is based on the excessive expression of ALS and the enhancement of tribenuron-methyl metabolism resulting from GSTs,not due to the sensitivity of ALS.In the meanwhile POD and SOD may play a role in alleviating the spray injury.