Imazaquin Absorption, Translocation, and Metabolism in Flue-Cured Tobacco

Abstract

Absorption of14C-imazaquin by leaves of field-grown flue-cured tobacco was similar when applied to young seedlings immediately after transplanting or to plants 3 wk after transplanting. The distribution of14C in treated leaves indicated that 40% was absorbed, 54% remained in water extracts of leaf surfaces, and 6% was found in the epicuticular wax layer 8 d after treatment. Translocation of the herbicide from treated leaves to roots was very low (4 to 5%). In contrast, soil applications of imazaquin and subsequent uptake by roots resulted in retention of 40 to 53% in roots and translocation of 47 to 60% to shoots after 8 d. Analyses of methanol-soluble extracts of14C indicated that more than 77% of the foliar-applied herbicide was metabolized in roots and upper shoots after 2 d. Similarly, 64% or more of the imazaquin was degraded in roots and shoots 2 d after root absorption.

Absorption, Translocation, and Metabolism of Foliar-applied Trifloxysulfuron in Tobacco

“…and false-green kyllinga (K. gracillima L.) rapidly absorbed 14 C-trifloxysulfuron between 0 and 4 HAT, with an accumulation of 47% 14 Cherbicide after 96 h. Troxler et al (2003) observed that purple and yellow nutsedge quickly absorbed 14 C-trifloxysulfuron between 0 and 4 HAT and approximately 55% of applied after 96 h. Askew and Wilcut (2002) reported that cotton (Gossypium hirsutum L.), jimsonweed (Datura stramonium L.), peanut (Arachis hypogaea L.), and sicklepod [Senna obtusifolia (L.) Irwin and Barnaby] all rapidly absorbed 14 Ctrifloxysulfuron between 0 and 4 HAT, but total absorption after 72 h varied by species between 30 and 70%. By comparison, tobacco absorbed 40% of applied 14 C-imazaquin 8 d after treatment (Walls et al 1993).…”

“…foliar-applied 14 C-imazaquin basipetally (Walls et al 1993). Typically, sulfonylurea herbicides move more readily in the xylem than in the phloem (Hageman and Behrens 1984;Lycan and Hart 1999;Petersen and Swisher 1985).…”

“…Tobacco metabolized 14 C-trifloxysulfuron rapidly, with 61% of the absorbed herbicide remaining in the parent herbicide form 4 h after treatment, whereas only 12.1% remained after 72 h. Extrapolated half-life of 14 C-trifloxysulfuron in tobacco, as calculated by other researchers (Askew and Wilcut 2002;Newsom et al 1993;Shaner and Robson 1985;Troxler et al 2003;Wilcut et al 1989), was 0.8 d. By comparison, Askew and Wilcut (2002) reported an identical 14 C-trifloxysulfuron half-life in cotton (a tolerant species), compared with 6 d in peanut (a susceptible species). Walls et al (1993) reported that 62 and 78% of foliar applications of 14 C-imazaquin was degraded in tobacco foliage after 2 d.…”

Tobacco Response to Residual and In-Season Treatments of CGA-3626221

“…Imazaquin is a member of the imidazolinone herbicide family and is an ALS-inhibiting herbicide (Devine et al 1993). Walls et al (1993) also reported tobacco tolerance to imazaquin applied early POST, but unacceptable injury resulted from preplant-incorporated (PPI) treatments. Tobacco is a common rotational crop with cotton in North Carolina.…”

Nicosulfuron tolerance and population dynamics of woolly cupgrass (Eriochloa villosa)

“…Many herbicide translocation studies demonstrated that radio-labeled herbicide appeared below and above the treated leaf and represented herbicide that was translocated out of the treated leaf (Hinz and Owen 1996;Lym 1992;Nimbal 1995;Walls et al 1993). Some snidies reported more radio-labeled herbicide in the leaf below the treated leaf than in the leaf above the treated leaf (Hinz and Owen 1996).…”