Movement and Fate of p-Nitrophenyl-α,α,α-Trifluoro-2-Nitro-p Tolyl Ether-1′-¹⁴C in Peanut Seedlings

Abstract

Abstract. Autoradiographs and liquid scintillation counts of peanut (Arachie hypogaea L., var. Starr) seedlings indicate that p-nitrophenyl-acy,a.trifluoro-2-nitro.p.tolyl ether-l'-14C (C-6989) is rapidly absorbed from nutrient solution but only 6.5 % of the radioactivity absorbed is translocated to the shoot after 144 hr, with the acropetal movement being confined to the stem and petiole.Metabolism of C-6989 by peanut seedlings proceeds rapidly, the major pathway being hydrolysis of the ether linkage and reduction of the 4-nitrophenol formed to 4-aminophenol. After 48 hr 4-aminophenol, C-6989 and 4-nitrophenol comprised 67.8, 17.4, and 13.5 % of the total radioactivity recovered, respectively. After 144 hr these compounds comprised 94.3, 4.0, and 0.9 % of the radioactivity, respectively.Reduction of one of the nitro groups of C-6989 followed by hydrolysis of the ether linkage is a minor pathway of metabolism in peanut seedlings. Small amounts (less than 1.0 % of the total radioactivity) of both P-nitrophenyl-a,a,a-trifluoro-2-amino-p-tolyl ether and p-aminophenyl-a,a,a-trifluoro-2-nitro-ptolyl ether were present but no p-aminophenyl-a,a,c-trifluoro-2-amino-p-tolyl ether was detected. Two very minor metabolites (less than 0.1% of the radioactivity) were detected which were not identified. These metabolites were possibly conjugates of the phenol derivatives with natural plant constituents. or products of substitutionl on, or ring cleavage of, the phenols. Approximately 50 % of the radioactivity persisted as C-6989, whereas p-aminophenyl-a,a,a-trifluoro-2-amino-p-tolvl ether (p,2-diamino-C-6989) was also detected in both species.Williams (9)

DEGRADATION OF FLUORODIFEN‐1′‐14C BY PEANUT SEEDLING ROOTS

“…Extracts were concentrated by rotary vacuum evaporation. Radioactivity was separated by thin-layer chromatography (Eastin, 1969a) and located by autoradiography as previously described (Eastin, 1969b). The radioactive spots were scraped ofl" the plates and quantified by liquid scintillation counting.…”

“…Long Green) (Rogers, 1969), morning glory {Ipomoea hederacea (L.) Iaeq.) (Walter et al, 1970), peanut (Eastin, 1969b;Walter et al, 1970), sorghum {Sorghum vulgare Pers.) (Waher et al, 1970) and soybean (Rogers, 1969;Geissbuhler, 1970;Walter e^fl/., 1970).…”

“…Rogers (1969) reported that 50% ofthe radioactivity in cucumber and soybean persisted as fluorodifen, with some j6-aminophenyl-a,a,a-trifluoro-2amino-/>-tolyl ether being detected. Eastin (1969b) found only 4% oi the radioactivity as fluorodifen in peanut seedlings after 144 h.…”

“…This investigation was conducted to further elucidate the pathway of degradation of fluorodifen in peanut seedling roots since very little radioactivity is translocated to the shoot of this species (Eastin, 1969b).…”

The Persistence and Movement of Fluorodifen in Soils and Plants

“…Limited movement of ^'''G-labelled herbicide was found in seedling peanuts [Arachis hypogaea L. cv. Starr) using autoradiography and liquid scintillation spectrometry (Eastin, 1969). The presence of a CF3 and two NO2 groups on the herbicide molecule indicated that it could be readily detected using electron-capture gas chromatography.…”