MOVEMENT AND FATE OF FLUORODIFEN‐1′‐¹⁴C IN CUCUMBER SEEDLINGS

Abstract

Summary. Autoradiographs and liquid scintillation counts of cucumber (Cucumis sativus L. cv. Ashley) seedlings indicated rapid absorption and translocation of radioactivity from fluorodifen‐1′‐14C (p‐nitrophenyl‐α,α,α‐trifluoro‐2‐nitro‐p‐tolyl ether labelled with 14C in the 1 position of the p‐nitrophenyl ring). After 24 h in 1 mg/1 of fluoro‐difen‐1′‐14C, 25% of the absorbed radioactivity was translocated from the roots. Cucumber seedlings degraded fluorodifen‐1′‐14C via a pathway similar to that reported for peanut seedlings but at a slower rate. The major degradation products were p‐nitrophenol and an unidentified polar compound (Unknown I). More rapid absorption and translocation coupled with slower degradation by cucumber as compared with peanut seedlings are factors which may contribute to the susceptibility of cucumber to fluorodifen.

Penetration, Translocation, and Metabolism of Acifluorfen in Soybean (Glycine max), Common Ragweed (Ambrosia artemisiifolia), and Common Cocklebur (Xanthium pensylvanicum)

“…The greater penetration and translocation coupled with slower metabolism by common ragweed and common cocklebur, compared to soybean, are factors that may contribute to the susceptibility of these weed species to acifluorfen. These results are similar to those of other investigators (4,5,8,17) who have examined the selectivity of other diphenylether herbicides to plants. be influenced both physically and physiologically by the relative humidity of the microclimate around the plant (1).…”

“…Acifluorfen is used for broadleaf weed control in soybean [Glycine max (L.) Merr.] (3,4). Investigators have obtained good control of many problem weeds such as common cocklebur and morningglory (Ipomoect spp.)…”

“…Eastin (1,2,3,4,5) was one of the first reserachers to propose a pathway of degradation for a diphenylether herbicide. His work (1) with fluorodifen (p -nitrophenyl 'Q,Q,Qtrifluoro -2 -nitrop -tolyl ether) in peanut (Arachis hypogaea L.) seedlings showed rapid metabolism.…”

Root Uptake, Translocation, and Metabolism of Nitrofluorfen and Oxyfluorfen by Fababeans(Vicia faba)and Green Foxtail(Setaria viridis)

“…Fadayomi and Warren (5) found limited translocation of oxyfluorfen from the roots to the shoots of sorghum [Sorghum bicolor (L.) Moench] or pea (Pisum sativum L.). Similar results were found with fluorodifen (pnitrophenyl a,a,a-trifluoro-2-nitro-p-tolyl ether) where herbi cide uptake by the roots was rapid, but translocation to the shoots was limited (3,4,12).…”

“…Degradation of diphenylether herbicides occurs via several pathways. A major pathway shown for fluorodifen is hydroly sis of the ether linkage and subsequent conjugation with plant constituents (3,4,10,11). Nitrofen (2,4-dichlorophenyl-pnitrophenyl ether) metabolism occurs by ring cleavage, unlike fluorodifen which is not cleaved at the ether bond (6) 3 .…”