ISSN:
1365-3180
Quelle:
Blackwell Publishing Journal Backfiles 1879-2005
Thema:
Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
Notizen:
Summary. The pathway and the rate of breakdown of C-1983 in bacterial suspensions, soil samples and plants was investigated with the 14C-carbonyl-labelled herbicide.Bacterial suspensions derived from humus soil were demonstrated to metabolize C-1983 [I] to N'-(4-chloropheuoxy)-phenyl-N'-methylurea [II], N'-(4-chlorophenoxy)-phenylurea [III] and (4-chlorophenoxy)-aniline [V]. In addition, at least two minor, unidentified metabolites were observed.In samples of humus soil and sandy loam, the pathway of degradation was found to be essentially the same as in bacterial suspensions. The rate of breakdown was slightly higher in sandy loam (35% loss in 8 weeks) than in humus soil (25% loss) under optimal growth conditions (temperature, humidity). In humus soil, which is highly adsorptive for C-1983, breakdown decreased with time, thereby suggesting that desorption of herbicide was too slow to maintain sufficient soil solution concentration. In auloclaved humus soil, breakdown was considerably less pronounced (15% loss in 16 weeks) than in non-autoclaved samples.Under model conditions (irradiation with ultra-violet source of 300 W) photo-destruction of C-1983 was found to be rapid (90% loss within 13 hours).From roots and leaves of Zea mays, Vicia faba and Phaseolus vulgaris, the same metabolites as given above (compounds [II] and [III]) were recovered in significant amounts. Furthermore, some minor, unidentified labelled compounds and varying amounts of residual radioactivity (not extracted by acetone) were observed. Evolution of 14CO2 was slow. Upon following the breakdown of C-1983 as a function of time in two weed species, Polygonum convolvulus was demonstrated to metabolize C-1983 more rapidly than Galinsoga parviflora.The implications of the present results are discussed in terms of the biological breakdown of C-1983 in soils under field conditions, the susceptibility of different plant species towards C-1983, and the determination of residue values in plant tissues and soils.Le comportement de la N'-(4-chlorophénoxy)-phényl-NN-diméthylurée (C-1983) dans les sols et dans tes plantesIII. Dégradation dans tes sais et dans les plantes
Materialart:
Digitale Medien
URL:
http://dx.doi.org/10.1111/j.1365-3180.1963.tb00248.x
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