The Resistance Of Capsella Bursa-pastoris To Tribenuron-methyl In Winter Wheat Fields In Northern China

In order to investigate the resistance of Capsella bursa-pastoris to tribenuron-methyl, 13 potential resistant biotypes were collected from winter wheat fields of 13 cities in Shandong, Shanxi, Henan, Hebei, and Shaanxi Provinces, and 13 susceptible biotypes were correspondingly collected from the nearby non-farming lands never applied herbicides. Based on the work done above, the biotypes from Zhumadian in Henan Province were selected, and the enzymology mechanism of resistance was discussed by the research on the target enzyme acetolactate synthase (ALS), important plant metabolic enzyme glutathione-s-transferase (GSTs), and the protective enzyme (SOD, POD, CAT). The cross-resistance of Capsella bursa-pastoris to bensulfuron-methyl, fluroxypyr meptyl, thifensulfuon methyland 2,4-D 1-butyl ester was researched.The results are as follows:ⅠThe resistance level detection of Capsella bursa-pastoris to tribenuron-methyl1. The results of seed bioassay showed that the relative resistance factor of Zhumadian in Henan Province was 6.17,which was the highest. All the other potential resistant biotypes were sensitive to tribenuron-methyl, with a resistance factor ranging from 0.94 to 2.04.2. The results of whole-plant bioassay showed that the relative resistance factor of Zhumadian in Henan Province was 232.93, while other potential resistant biotypes were 1.23 to 3.73. The results showed that the resistance of potential resistant biotypes of Capsella bursa-pastoris from Zhumadian in Henan Province to tribenuron-methyl was higher than others.ⅡThe resistance mechanism of Capsella bursa-pastoris to tribenuron-methylThe biotypes from Zhumadian in Henan Province were selected and the enzymology mechanism of resistance was discussed. The results are as follows:1. In vivo, there was significant difference of ALS sensitivity in vitro between the resistant and susceptible biotypes to tribenuron-methyl, with the IC50 0.7228 and 0.0521μM, and then the relative resistance factor to tribenuron-methyl was 13.87. ALS sensitivity was one cause for the resistance.2. In vitro, the ALS activity of the resistant populations was decreased firstly, then turned to increase slowly; the ALS activity of the susceptible populations, however, was inhibited significantly, and was irreversible.3. The GSTs activity of resistant biotype was higher than that of susceptible biotype on the whole. The correlation between herbicide resistance and GSTs activity indicated that the difference of metabolizable ability of GSTs to tribenuron-methyl is the other important reason of the resistance to tribenuron-methyl.4. No significant difference existed between resistant and susceptible biotypes about antioxidant enzyme (POD, SOD and CAT). The activity of antioxidant enzyme is not related to the resistance of tribenuron-methyl to Capsella bursa-pastoris.ⅢThe cross-resistance of Capsella bursa-pastorisThe result of cross-resistance showed that the resistant biotype of Capsella bursa-pastoris was resistant to ensulfuron-methyl and fluroxypyr meptyl, with the resistance factor 9.1 and 11.0, while was still susceptible to 2,4-D 1-butyl ester and fluroxypyr meptyl.