METABOLISM OF [RING-2,6-C-14]PARATHION IN PLANT-CELL SUSPENSION-CULTURES OF CARROT (DAUCUS-CAROTA), PURPLE FOXGLOVE (DIGITALIS-PURPUREA), SOYBEAN, THORN-APPLE (DATURA-STRAMONIUM) AND WHEAT (TRITICUM-AESTIVUM)

means of standardized procedures, the metabolism of [ring-2,6-C-14]-pa rathion was investigated in carrot (Daucus carota L.), purple foxglove (Digitalis purpurea L.), soybean (Glycine max Merrill cv. 'Mandarin', and Glycine max Merrill cv. 'Harosoy 63' cultivated on B5 and Miller media, respectively), thorn apple (Datura stramonium L.), and wheat (T riticum aestivum L.) cell suspension cultures. In the wheat and soybea n (Mandarin) cells only 2.9 and 8.9%, respectively, of the applied par thion remained unmetabolized after 48 h of incubation, while 51.2, 57. 9, 60.3, and 62.4% of the unchanged parent were detected in the D. pur purea, D. Stramonium, carrot and soybean (Harosoy) cultures, respectiv ely. In all suspensions, paraoxon and 4-nitrophenol were found as phas e I metabolites, thus demonstrating that plant tissues can catalyse ox idative desulfuration and dearylation of parathion. 4-Nitrophenol was also glycosylated with glucose and possibly galactose. Further, as yet unidentified, metabolites indicated that biotransformations had also occurred at the aromatic moiety. Large amounts of non-extractable resi dues were detected in the wheat suspension (38.3%), while the other cu ltures showed a lower incorporation of C-14 into insoluble cell materi al (0.9-9.4%). For a prospective ecotoxicological evaluation of the me tabolic fate of pesticides and xenobiotics in plants in general, the d ifferential metabolic capacity of plant cell cultures and plants shoul d be taken into account.