Abstract: The effects of quinclorac on growth characteristics, protein concentration, peroxidase activity, superoxide dismutase activity and auxin content in Echinochloa crusgalli were studied by applying quinclorac and auxin. The results showed that the treatment of 800 g·hm-2 quinclorac for 24 h did not significantly inhibit the growth of S-type barnyardgrass. However, the average fresh weight of R-barnyardgrass was significantly increased by quinclorac treatment alone and the treatment of quinclorac with IAA. Under the conditions of no medicine application, quinclorac treatment alone and the treatment of quinclorac with IAA, the protein concentration of R-type barnyardgrass increased by 23.5%, 29.8% and 64.0% than that of S-type barnyardgrass respectively. R-type barnyardgrass showed higher tolerance. After treated with quinclorac, the SOD activity of two biotypes of barnyardgrass increased and the POD activity decreased. Exogenous IAA can enhance the POD activity of S-type barnyardgrass; while there was no significant effect on SOD, POD activity of R-type barnyardgrass. The increase of auxin content promoted the growth of R-type barnyardgrass.

Key words: herbicide resistant weed, herbicide resistant mechanism, Echinochloa crusgalli, quinclorac, auxin

摘要： 通过外施二氯喹啉酸、生长素处理，研究二氯喹啉酸对稗草Echinochloa crusgalli生长特性、蛋白浓度、过氧化物酶及超氧化物歧化酶活性、生长素含量的影响。结果表明，800 g·hm-2二氯喹啉酸处理24 h未对S型稗草的生长产生明显抑制，而二氯喹啉酸单独处理及外施IAA的二氯喹啉酸处理均能显著增加R型稗草鲜重。在不施药、二氯喹啉酸单独处理、二氯喹啉酸与IAA共同处理的条件下，R型稗草比S型稗草的蛋白浓度分别提高23.5%、29.8%和64.0%，R型稗草表现出较高的抗逆境耐受能力。经二氯喹啉酸处理后，两种生物型稗草SOD活性上升，POD活性下降。施外源IAA能提高S型稗草POD活性，而对R型稗草SOD、POD活性影响不显著。提高生长素含量可显著促进R型稗草的生长。

关键词: 抗药性杂草, 抗药性机制, 稗草, 二氯喹啉酸, 生长素