Absorption and fate of carfentrazone-ethyl inZea mays, Glycine max,andAbutilon theophrasti

Abstract

Carfentrazone-ethyl absorption, translocation, and metabolism was determined in Glycine max, Zea mays, and Abutilon theophrasti. Glycine max absorbed greater than 90% of applied carfentrazone-ethyl within 2 h after treatment (HAT) when nonionic surfactant (NIS) or crop oil concentrate (COC) were included in the treatment solution. The addition of 28% urea ammonium nitrate (UAN) did not improve carfentrazone-ethyl absorption in G. max, but in Z. mays and A. theophrasti, UAN combined with NIS or COC increased the rate of carfentrazone-ethyl absorption. Carfentrazone absorption in A. theophrasti 2 HAT was 70% when UAN was combined with NIS or COC compared to 40% with NIS or COC alone; however, 24 HAT, absorption with NIS and COC were similar to treatments with UAN. Carfentrazone-ethyl did not translocate from the treated leaf to other plant parts in Z. mays and only small amounts of radiolabeled product were detected in the rest of the shoots of A. theophrasti (5%) and G. max (12%). Herbicide metabolism in Z. mays and G. max was greater than in A. theophrasti. All three species converted carfentrazone-ethyl to its phytotoxic metabolite carfentrazone-chloropropionic acid; therefore, the parent molecule was considered to be the sum of the ethyl ester and its hydrolysis product. Estimated half-lives of carfentrazone in Z. mays, G. max and A. theophrasti were 1, 7, and 40 h, respectively. The rate of carfentrazone metabolism corresponded to plant sensitivity (sensitivity to carfentrazone: Z. mays<G. max<<A. theophrasti); however, rapid absorption and translocation of carfentrazone may reduce the tolerance of G. max.

Absorption and Translocation of Aminocyclopyrachlor and Aminocyclopyrachlor-Methyl Ester in Canada Thistle (Cirsium arvense)

“…The protoporphyrinogen oxidase inhibitor, carfentrazone ethyl ester, was reported to be almost totally metabolized to the phytotoxic free acid 2 HAT in velvetleaf (Abutilon theophrasti Medik.) (Thompson and Nissen 2000). Recent studies have also shown that specific enzymes, such as AmGDSH1, localized in the apoplast, hydrolyzed 2,4-D methyl ester to release the phytotoxic acid 2,4-D ).…”

“…This rapid conversion to the free acid would promote a strong concentration gradient across the cuticle, whereas the free acid is physiologically suited to long-distance phloem transport. Carfentrazone-ethyl ester, fluazifop-P butyl ester, and various auxinic herbicide esters are just a few examples of herbicides applied as proherbicides, which require plant esterase activity for bioactivation to produce the herbicidal free acid (Thompson and Nissen 2000).…”

Effets du désherbage et de la fertilisation foliaire sur la productivité du maïs fourrager(Zea maysL.) dans les sols calcaires tunisiens

“…Il est connu que certains engrais tels que l'urée stimule l'absorption des herbicides mais également celle des éléments nutritifs (Bowman & Paul, 1992). Certains travaux ont montré que l'absorption de la Carfentrazone éthyle par des plants de maïs est stimulée en présence de l'urée (Thompson & Nissen, 2000).…”

Genotypic variation of metribuzin and carfentrazone-ethyl tolerance among yellow lupin (Lupinus luteusL.) germplasm

“…Selecting tolerant genotypes has improved metribuzin tolerance in cultivars of soybean, wheat and narrowleafed lupin (Barrentine et al 1982;Schroeder et al 1985;Si et al 2006). Selectivity to carfentrazone-ethyl is also found between soybean and broad-leaved weeds (Thompson & Nissen 2000). This paper reports the genotypic variation and identification of sources of tolerance to metribuzin and carfentrazone-ethyl in yellow lupin germplasm.…”