Metabolism and cell wall incorporation of phenoxyacetic acid in soybean cell suspension culture

The metabolism of \C-14\ phenoxyacetic acid (POA) was studied in cell suspe nsion culture of soybean (Glycine max). POA was metabolized to 4-HO-POA, 4- HO-POA glucoside and 4-HO-POA glycosidic ester. A large part of the 4-HO-PO A glucoside and small amounts of the glycosidic ester were recovered in the medium. POA was also converted to non-extractable residues bound to cell w alls. Sequential extraction of cell-wall polymers showed that non-extractab le residues, partly identified with 4-HO-POA and POA, were mainly associate d with hemicelluloses and lignin. Comparison of the metabolism of [carboxy- C-14] - and [phenyl-C-14] POA revealed some degradation of the POA sidechai n, followed in all probability by the incorporation of the aromatic moiety into cell walls. However, the sturdiness of the resulting bonds prevented p recise identification of these bound aromatic structures. In summary, the d egradation of POA in soybean cell culture provided a good model to study th e formation of non-extractable residues of pesticides. (C) 1999 Society of Chemical Industry.