Absorption, translocation, and fate of propyzamide in witloof chicory (Cichorium intybus L.) and common amaranth (Amaranthus retroflexus L.)

Abstract

Summary Witloof chicory (Cichorium intybus L.) is tolerant to propyzamide and common amaranth (Amaranthus retroflexus L.) is sensitive. The absorption, translocation, and metabolism of propyzamide was studied in seedlings of witloof chicory and common amaranth to determine if differences in these processes cause the differential sensitivity. At 24,48, and 72 h after root treatment, there was no difference in the concentration of 14C (g−1 plant dry wt) in com‐mon amaranth and witloof chicory. Approximately 50% of the absorbed 14C was translocated out of the roots to shoots of both species at 24 and 48 h after treatment. After 72 h about 55 and 74% of the absorbed 14C was translocated to shoots of witloof chicory and common amaranth, respectively. Distribution of 14C (g−1 plant dry wt) in plant parts of witloof chicory and common amaranth seedlings was similar. Roots of both species accumulated the highest concentration of total 14C, whereas shoots contained the lowest. Thin layer chromatography revealed that the herbicide was metabolized in neither species 48 h after treatment. No differences were found in absorption, translocation, or metabolism between witloof chicory and common amaranth with regard to propyzamide.

First Report of Pronamide-Resistant Annual Bluegrass (Poa annua)

“…Shoot and root residues were dried in a hood for 72 h and then combusted, and radioactivity was calculated with the previously mentioned methods. Extraction efficiency ranged from 85 to 97% and was comparable to levels reported in previous research (Mersie et al 1995; Rouchaud et al 1987).…”

“…The R f of [ 14 C] pronamide was identified at 0.69, and three metabolites were detected at 0.1, 0.4, and 0.9 in both annual bluegrass biotypes (Figure 3). These R f values are consistent with previous research on pronamide metabolism in common amaranth, lettuce, and chicory, using the same chromatography methods (Mersie 1995;Rouchaud et al 1987). The metabolite at R f 0.1 was identified as 3,5-dichlorobenzoic acid through co-chromatography with the standard, similar to previous research (Rouchaud et al 1987).…”

“…Shoot and root residues were dried in a hood for 72 h and then combusted, and radioactivity was calculated with the previously mentioned methods. Extraction efficiency ranged from 85 to 97% and was comparable to levels reported in previous research (Mersie et al 1995;Rouchaud et al 1987).Thin-layer chromatography (TLC) analysis was then conducted to evaluate metabolites. The supernatant was evaporated in a forced-air hood, and samples were resuspended in 100-μl of acetone.…”

“…Differential levels of translocation have been previously reported between species susceptible and tolerant to pronamide. Mersie (1995) found 74% and 55% of the absorbed radioactivity from root-applied [ 14 C]pronamide was translocated to shoots after 72 h in a susceptible species, common amaranth, and a tolerant crop, chicory, respectively. Reduced levels of translocation after foliar absorption have also been associated with resistance to other herbicides, including glyphosate and paraquat (Shaner 2009; Yu et al 2007).…”

“…Metabolism of [ 14 C]Pronamide. The metabolism of pronamide was evaluated with a modified methodology from previous research with lettuce (Lactuca sativa L.), chicory (Cichorium intybus L.), and redroot pigweed (Amaranthus retroflexus L.) (Mersie et al 1995;Rouchaud et al 1987). Fifteen plants of the two biotypes (30 total plants) were grown hydroponically for 1 wk in the growth chamber using the aforementioned methodology.…”