Herbicide resistance in Aster squamatus conferred by a less sensitive form of acetolactate synthase.

摘要: A biotype of Aster squamatus (Sprengel) Hieronymus with suspected resistance to the ALS-inhibiting herbicide imazapyr was detected in a chicken farm province Seville, Spain, which had been treated once year for 10 years. Resistance this studied using dose–response experiments, absorption and translocation assays, metabolism studies ALS activity assays. The rate required inhibit growth by 50% (ED50) 15 times higher R (resistant) than S (susceptible) biotype. Cross-resistance existed ALS-inhibitors imazamox, imazethapyr, amidosulfuron, nicosulfuron, rimsulfuron, triasulfuron tribenuron, but not bensulfuron. Control alternative herbicides poor clopyralid, intermediate quinclorac, amitrole MCPA, excellent 2,4-D, glufosinate glyphosate. Absorption [14C]imazapyr increased over time both biotypes, from leaf shoots roots similar most radioactivity remaining leaf. No metabolites were either Sensitivity enzyme (target site) lower (I50(R) = 4.28 × I50 (S)). mechanism appears be an altered conferring decreased sensitivity at whole-plant level. Copyright © 2003 Society Chemical Industry