Studies on the tolerance to new herbicide pyribambenz-propyl in oilseed rape

摘要

Experiments were conducted to investigate the tolerance, its mechanism and the best concentration of PP (Pyribambenz-propyl) and Bispyribac-sodium (BS, Nommnee) in Brassica rapa (including 4 varieties), B. juncea and B. napus determined as the activity of acetolactate synthase (ALS). The results indicated that the ALS activities of PP treatments under higher concentration (500 and 1000 mg/l) were significantly lower than that of the control, while the treatment of PP at low concentration (100 mg/l) showed the higher ALS activity. B. rapa was more sensitive to PP than other two Brassica species (which was 7.7% lower than that of B. juncea), and B. napus showed the medium tolerance. Within 4 cultivars of B. rapa,Changshaguihuazi and Xiaoyoucai were more sensitive than the other two cultivars. Cultivar Jianghuang showed the highest resistance, with the 6.5% higher of ALS activity compared to Changshaguihuazi, the most susceptible variety. Further study indicated that the ALS activity increased at 14 days, then began to fall at 28 days (except for 1000 mg/l). Among the all treatments,the 100 mg/l PP played an important role in the promotion of the enzyme effect and improved the growth of plants.