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1.
The uptake and translocation of [14C]asulam (methyl 4-aminophenyl-sulphonylcarbamate), [14C]aminotriazole (1-H-1,2,4-triazol-3-ylamine) and [14C]glyphosate (N-(phosphonomethyl)glycine) were assessed in Equisetum arvense L. (field horsetail), a weed of mainly horticultural situations. Under controlled-environment conditions, 21°C day/18°C night and 70% r. h., the test herbicides were applied to 2-month-old and 2-year-old plants. Seven days following the application of 0.07-0.09 °Ci (1.14mg) of the test herbicides to young E. arvense, the accumulation of 14C-label (as percentage of applied radioactivity) in the treated shoots, untreated apical and basal shoots was as follows: [14C]asulam, 13.2, 0.18 and 1.02%; [14C] aminotriazole, 67.2, 3.65 and 1-91%; [14C]glyphosate, 35.9, 0.06 and 0.11%. The equivalent mean values for the accumulation of 14C-label in 2-year-old E. arvense were [14C]asulam, 12.0, 1-15 and 1.74%; [14C]aminotriazole, 58.6, 9.44 and 4.12%; [14C]glyphosate, 33.1, 0.79 and 2.32%. In the latter experiment, test plants received 0.25-0.30 °Ci (4mg) of herbicide, they were assessed after a 14-day period and the experiment was carried out at 3-week intervals between 2 June and 25 August on outdoor-grown plants. Irrespective of test herbicide or time of application, very low levels of 14C-label accumulated in the rhizome system. Only 0.2% of the applied radioactivity was recovered in 2-year-old plants and 0.4% in 2-month-old plants. In the young plants [14C]asulam accumulated greater amounts and concentrations of 14C-label in the rhizome apices and nodes than [14C]aminotriazole or [14C]glyphosate treatments. Inadequate control of E. arvense under field conditions may be due to limited basipetal translocation and accumulation of the test herbicides in the rhizome apices and nodes. 相似文献
2.
The uptake and translocation of 14C-ring-labeled asulam (methylsulfanilcarbamate) and bromacil (5-bromo-3-sec-butyl-6-methyluracil), were compared after root application to maize (Zea mays L.) and bean (Phaseolus vulgaris L.). Autoradiographs showed the distribution of bromacil throughout these and other plant species, and the retention of asulam in the roots. The recovery of both compounds in quantitative radioassays was between 90 and 100%. The absorption of bromacil and asulam was rather similar. Absorption of bromacil increased up to 20% of the applied dose in bean plants after 2 days of exposure, and up to 11% in maize plants after 4 days. Absorption of asulam in bean plants was 22% of the applied dose after 2 days, and 8% in maize plants after 4 days. The pattern of distribution of bromacil and asulam was completely different. After 4 h of exposure of the roots about half of the absorbed bromacil had accumulated in the shoots, while two-thirds or more was translocated to the shoots after exposure periods of 1 to 4 days. Not more than one-eighth of the absorbed asulam was found in the shoots. In consequence, the bromacil content in the transpiration stream relative to that in the ambient solution was much higher than that of asulam. The leakage of asulam from bean and maize roots into herbicide-free nutrient solution was lower than that of bromacil. The reasons for these differences are not yet clear. There was only some metabolism of asulam in maize, but not in bean plants. No metabolites of bromacil were detected in the two plant species. 相似文献
3.
Studies of the absorption and translocation of foliage-applied ring-labelled [14C]asulam [methyl (4-aminobenzenesulphonyl) carbamate] were carried out using glasshouse and field-grown bracken plants. Translocation of 14C from the treated frond was primarily according to a 'source to sink’pattern with intense accumulation of radioactivity in the metabolically active sinks viz. rhizome apices, frond buds, root tips and young frond tissue. In the case of field bracken, translocation and distribution of 14C was extensive in the rhizome system, accumulation occurring in the active as well as dormant buds situated on the non-frond-bearing and storage rhizome branches. Treatment of fully expanded fronds with 100μl of [14C]asulam (1 mg, 1.0–1.5 μCi) as 2 μl droplets resulted in a rapid initial uptake during the first week, followed by progressive entry and distribution with time. Basipetal translocation to the rhizome system was positively correlated with total uptake. High humidity (95%) and high temperature (30°C) stimulated uptake and subsequent basipetal translocation to a considerable degree. Uptake was greater through the stomatal-bearing abaxial than through the adaxial cuticle. Incorporation of a surfactant (Tergitol-7, 0.1%) increased penetration by up to 30%. Uptake declined markedly as the frond aged, while translocation was predominantly acropetal in young treated fronds, becoming exclusively basipetal when the fronds matured. Optimum uptake and maximum distribution of [14C]asulam in the rhizome and its associated buds was achieved when treatments were applied to almost fully expanded fronds. The translocated 14C (asulam and possibly some of its metabolites) showed a considerable degree of persistence in the rhizome system, 8% of the applied activity still remaining in the rhizome 40 weeks after treatment. 相似文献
4.
The effect of non-ionic nonylphenol (NP) surfactants containing 4–14 ethylene oxide (EO) molecules on the distribution of asulam and diflufenican was investigated in Pteridium aquilinum L. Kuhn and Avena fatua L. The distribution of the herbicides was dependent on the EO content and concentration of surfactant and differed between plant species and herbicide. The surface properties of contact angle, droplet diameter and surface tension were examined. For solutions of asulam, the greatest reductions in contact angle, surface tension and greatest droplet diameter were obtained with surfactants of EO 6.5–10 (at 0.001–0.1%). For solutions of diflufenican, these responses were greatest when applied with surfactant of EO 4. Surfactants of EO 6.5–10 increased the uptake and translocation of [14C]asulam in P. aquilinum, particularly at surfactant concentrations of 0.01 % and 0.1 %. All surfactants increased uptake of [14C]asulam in A. fatua with no significant effects of surfactant EO number or concentration. For both species, there was a positive correlation between the optimum surface characteristics of the herbicide droplets and the uptake of asulam. With diflufenican, greatest uptake and translocation by mature frond tissue of P. aquilinum occurred at the highest concentration of surfactant EO 4; in A. fatua, however, uptake and translocation were not significantly affected by any of the surfactants. 相似文献
5.
The possible relationship between folate levels in plants and their tolerance to asulam has been examined. Plants with a high content of folates were relatively less susceptible to asulam. There was evidence of a depletion of the folates in the shoots of plants treated with asulam, either alone at 1. 1 kg ha?1 or in combination with 4, 6-diamino-1-(3, 4-dichlorophenyl)-1, 2-dihydro-2, 2-dimethyl-1, 3, 5-triazine (DCDT) at 1.1 kg ha?1. In wheat shoot tips (Triricum estivum L.), asulam at 1.1 kg ha?1 reduced the levels of the N5-methyl, N10-formyl and N5-formyl derivatives of 5, 6, 7, 8-tetrahydrofolates, particularly when applied in combination with DCDT. Studies with cell-free extracts of wheat seedlings revealed that asulam inhibited the enzymic synthesis of 7, 8-dihydro-pteroateina manner similar to sulphanilamide inhibition. The biochemical site of action of asulam in plants is discussed. 相似文献
6.
Translocation of 2,4-D, asulam and amitrole in water hyacinth 总被引：1，自引：0，他引：1
In glasshouse experiments foliar application or 14C-labelled herbicides to water hyacinth plants at the 4-leaf stage indicated that amilroie transport from the treated leaf blade was faster and greater than 2.4-D. but a little less than asulam. From the treated leaf 14·2, 25·9. 39·7. 44·5 and 51·8% of the recovered 14CNamitrole was translocated at intervals of 6 h. and 1. 3. 6 and 12 day., respectively. Both xylem and phloem transport of asulam and amitrole was evident, whereas 2.4-D moved only from ‘source to sink’. Movement of the herbicides from the mother to the connected daughter plant or vice versa was dependent upon the size of the latter. Maximum transport of these herbicides in either direction took place at the 2-leaf stage of daughter plants. With any increase or decrease in the number of leaves on daughter plants, the transport of herbicides was reduced. As an exception, daughter plant to mother plant movement of amilroie was maximum at the 1-leaf stage. After extraction, fractionation and TLC separation of foliage applied 14C-2.4-D 76–4 and 72·1% of the radioactivity was detected in the chloroform phase of the leaf extract at 3 and 6 day intervals, respectively. In another pot culture experiment, it was observed that after spraying the mother plants with 2.4-D-amine at 0–75 kg/ha the connected daughter plants at 1 to 4-leaf stages werckilled if the culture solution was contaminated while spraying, or by dying leaves. When contamination was totally avoided, the connected but unsprayed daughter plants at 3 to 4-feaf stages survived. 相似文献
7.
Mohammad Amzad Hossain Hitoshi Kuramochi Yukio Ishimine Hikaru Akamine 《Weed Biology and Management》2001,1(2):108-114
Field and glasshouse experiments were conducted from 1995 through 1996 to evaluate application timing of asulam (methyl sulfanilylcarbamate) for torpedograss (Panicum repens L.) control in relation to plant age in sugarcane. Above‐ground shoots of torpedograss were completely controlled with asulam at 2–4 kg active ingredient (a.i.) ha?1 applied 60 or 80 days after planting (DAP) in artificially infested pots. But some newly developed rhizome buds survived after asulam application resulting in 1–25 and 76–100% or more regrowth in 60 and 80 DAP‐applied pots, respectively. Whereas the herbicide at 2–4 kg a.i. ha?1 applied within 60 DAP completely controlled above‐ground shoots, applied 80 DAP at 2 kg a.i. ha?1 it did not completely control the weed in the artificially infested field. Regrowth levels were 1–25 and 76–100% or more in 60 and 80 DAP‐applied plots, respectively. Asulam at 2–3 kg a.i. ha?1 applied 20, 40, 60 or 80 DAP in a naturally infested field completely controlled above‐ground shoots and regrowth levels were 76–100 or more, 51–75, 1–25 and 26–50% in these same DAP applied plots, respectively. The herbicide applied at 4 kg a.i. ha?1 caused chlorosis on younger sugarcane leaves (one‐leaf stage), but when applied at 2–3 kg a.i. ha?1, no injury symptoms were shown. The herbicide at 2–4 kg a.i. ha?1 applied within 60 DAP resulted in remarkably higher yield and shoot biomass of sugarcane than that applied 80 DAP. This study suggested that asulam at 2–3 kg a.i. ha?1 should be applied 60 days after planting for the maximum control of torpedograss regrowth and better yield of sugarcane. This study also indicated that torpedograss cannot be completely controlled with a single application of asulam in a naturally infested field because of rhizome fragmentation by cross plowing and distribution of rhizomes into different soil layers that require different times to emerge. The shoots emerging after asulam application could not be controlled. Another study is required to determine the interval between sequential applications of asulam for better control of torpedograss in a naturally infested field. 相似文献
8.
Studies have been carried out on the herbicidal action of asulam [methyl (4-aminophenylsulphonyl)carbamate] and sulphanilamide, alone or in association either with 4-aminobenzoic acid (4ABA) or 4, 6-diamino-1-(3, 4-dichlorophenyl)-1, 2-dihydro-2, 2-dimethyl-1,3,5-triazine (DCDT). The soaking of wheat seeds (Triticum estivum L.) for 12 h at 30°C in asulam and DCDT in a 10:1 ratio doubled the inhibition of root growth produced by soaking in asulam alone; the addition of 4ABA partially reversed the activity of asulam. Foliar applications of a mixture of asulam + DCDT (1.1 + 0.55 kg ha?1) markedly increased the activity of asulam in susceptible wheat, wild oat (Avena fatua L.), tolerant flax (Linum usitatissimum L.), and in Stellaria media L. The activity of asulam at 1.1 kg ha?1 was reversed by 4ABA at 2.2 kg ha?1 by about 50% in wheat and wild oat, 82% in flax and 100% in S. media. The results indicate that asulam and sulphanilamide act by similar mechanisms in apparently inhibiting the biosynthesis of folic acid. 相似文献
9.
Summary. Tracer studies using single drops of solutions containing 3–amino-1,2,4–triazole-5–14 C (aminotriazole-14 C) or 2,2–dichloropropionic acid-2–14 C (datapon-14 C) revealed that in couch plants (Agropyron repens (L.) Beauv.) growing under field conditions in the autumn and at the stage where the aerial shoots were 40–50 cm long, both compounds moved in both symplast and apoplast. Dalapon was less mobile in the symplast than aminotriazole and only negligible amounts of dalapon were translocated to the rhizomes. The nodes of the treated shoots appeared to act as barriers to translocation, a phenomenon more pronounced for dalapon than for aminotriazole.
Application to a basal green leaf led to a more uniform distribution of the compounds within plants and rhizomes than when the application was made to the youngest fully-expanded leaf.
In couch plants with aerial shoots 10–15 cm long treated in the stubble, the distribution of both aminotriazole and dalapon was mainly restricted to the treated shoots. Even 15 days after application only trace amounts of radioactivity could be found in the rhizomes and untreated shoots. 相似文献
Application to a basal green leaf led to a more uniform distribution of the compounds within plants and rhizomes than when the application was made to the youngest fully-expanded leaf.
In couch plants with aerial shoots 10–15 cm long treated in the stubble, the distribution of both aminotriazole and dalapon was mainly restricted to the treated shoots. Even 15 days after application only trace amounts of radioactivity could be found in the rhizomes and untreated shoots. 相似文献
10.
ALLAN E. SMITH 《Weed Research》1984,24(4):291-295
The persistence of bromoxynil (3,5-dibromo-4-hydroxybenzonitrile), [14C]dicamba (3,6-dichloro-2-methoxybenzoic-7-14C acid) and propanil [N-(3,4-dichlorophenyl)propionamide] at rates equivalent to 1 kg ha?1, were studied under laboratory conditions in a clay loam, a heavy clay and a sandy loam at 85% of field capacity and at 20±1°C, both singly and in the presence of herbicides normally applied with these chemicals as tank-mix or split-mix components. The degradation of bromoxynil was rapid with over 90% breakdown occurring within a week in the heavy clay and sandy-loam soils, while in the clay-loam approximately 80% of the bromoxynil had broken down after 7 days. In all three soils degradation was unaffected by the presence of asulam, diclofop-methyl, flamprop-methyl, MCPA, metribuzin or propanil. Propanil underwent rapid degradation in all soil treatments, with over 95% of the applied propanil being dissipated within 7 days. There were no noticeable effects on propanil degradation resulting from applications of asulam, barban, bromoxynil, dicamba, MCPA, MCPB, metribuzin or 2,4-D. The breakdown of [14C]dicamba in a particular soil was unaffected by being applied alone or in the presence of diclofop-methyl, flampropmethyl, MCPA, metribuzin, propanil or 2,4-D. The times for 50% of the applied dicamba to be degraded were approximately 16 days in both the clay loam and sandy loam, and about 50 days in the heavy clay. 相似文献
11.
Low rates of picloram in mixture with glyphosate provided a rapid enhancement of the onset of injury to the shoots of Cirsium arvense (Canada thistle or creeping thistle) under field (0.07+1.0 and 0.07+1.5 kg ha?1) and greenhouse (0.035+0.42 and 0.07+0.84 kg ha?1) conditions. Picloram slightly reduced the amount of 14C-glyphosate absorbed at 24 and 48 but not 72 h after treatment. Movement of 14C-glyphosate from the treated leaves to the shoot apex, remainder of the shoot and roots was reduced in the presence of picloram. Necrosis of the treated leaves above the treated spots was evident, presumably indicating acropetal movement of either or both herbicides. With the picloram + glyphosate mixtures there was increased shoot regrowth over glyphosate alone at 1 year after treatment under field, and with certain mixtures at 18 days and 4 weeks after treatment under greenhouse conditions. Following application of the mixtures, accumulation of glyphosate in the shoots may be responsible for the enhanced onset of shoot injury while failure of enough glyphosate to translocate to, and cause death of, the roots may be responsible for the increased shoot regrowth over glyphosate alone. 相似文献
12.
The degradation and formation of major chlorinated metabolites of terbuthylazine and atrazine in three soils (loamy clay, calcareous clay and high clay) were studied in laboratory experiments using molecules labelled with 14C on the s-triazine ring. Soil microcosms were treated with the equivalent of 1 kg ha-1 of herbicide and incubated in the dark for 45 days at 20(±1)°C. The quantity of [14C]carbon dioxide evolved in the soils treated with atrazine was negligible and could not be attributed to mineralization of the parent molecule. The mineralization of terbuthylazine accounted for 0·9–1·2% of the initial radioactivity. In the soils studied, the extrapolated half-lives varied from 88 to 116 days for terbuthylazine and 66 to 105 days for atrazine, with no significant differences for the three soils and the two molecules. The deethyl metabolites of the two s-triazines and the deisopropyl-atrazine metabolite appeared during the incubation in the three soils. The completely dealkylated metabolite was not detected in any of the soils. After 45 days of incubation, the non-extractable soil residues for the high clay, loamy clay and calcareous clay soils represented for terbuthylazine, 33·5, 38·3 and 43·1% and for atrazine, 19·8, 20·8 and 22·3% of the initial radioactivity. © 1997 SCI. 相似文献
13.
A rat, given a single oral dose of [14C] cymoxanil, 1-(2-cyano-2-methoxyimino-[2-14C]-acetyl)-3-ethylurea, eliminated 91% of the radioactivity within 72 h. The urine contained 71%, the faeces 11%, and the expired air about 7% of the radiolabel; no 14C residue was found in the internal organs. Greater than 70% of the radioactivity in the urine was identified. The major metabolite was characterised as glycine, both free and conjugated, as hippuric acid and phenylaceturic acid [N-(phenylacetyl)-glycine], and probably in the form of polypeptides of low molecular weight. The other metabolites identified included 2-cyano-2-methoxyiminoacetic acid, 2-cyano-2-hydroxyiminoacetic acid and 1-ethylimidazolidine-2, 4, 5-trione. The minor metabolites included succinic acid and 2-oxoglutaric acid which indicated reincorporation of metabolic 14C. Cymoxanil, as such, was not detected in the urine. 相似文献
14.
Mohammad AmzadHossain YukioIshimine HitoshiKuramochi HikaruAkamine 《Weed Biology and Management》2002,2(2):92-97
Two field experiments each conducted during a 1 year period at the Agricultural Experiment Farm, University of the Ryukyus, Japan evaluated the interval needed between sequential applications of asulam (3 kg ai ha−1 ) for successful control of torpedograss ( Panicum repens L.). Regrowth of torpedograss from rhizomes was lowest when asulam was applied at 40-day intervals. Application at intervals of 70 days or longer completely controlled above-ground shoots but not regrowth from rhizomes. Above-ground biomass of torpedograss regrowth was 7- and 49-fold higher when asulam was applied at 70 and 100 day intervals, respectively, compared with 40-day intervals. Asulam applied three times at 40-day intervals starting 40 days after land preparation provided almost total torpedograss control 1 year after the initial application. 相似文献
15.
In three experiments, glyphosate (1.0 kg/ha) and aminotriazole (1.5 kg/ha) killed volunteer potatoes. Glyphosate (0.5 kg/ha) gave acceptable control in the field but not in the two pot experiments; in these latter, addition of ammonium sulphate to glyphosate improved its performance. Field applications of both herbicides at the end of May were less effective than those in June and July, because not all the sprouts had emerged in May. Aminotriazole killed those daughter tubers already pre sent, whilst glyphosate affected sprout viability and hence their ability to produce new plants. The practical potential of these two herbicides for the control of volunteer potatoes is discussed. Activité du glyphosate el de l'aminotriazole contre les repousses de pommes de terre et leurs tubercules fils Dans trois expériences, le glyphosate (1,0 kg/ha) et l'aminotria-zole (1,5 kg/ha) ont tue les repousses de pommes de terre. Le glyphosate (0,5 kg/ha) a fait preuve d'une efficacité acceptable au champ mais pas dans les deux expériences en pots; dans celles-ci, I'addition de sulfate d'ammonium au glyphosate a amélioré ses performances. Les applications au champ des deux herbicides à la fin de mai ont été moins efficaces que celles effectuées en juin et juillet parce que toutes les repousses n'étaient pas sorties en mai. L'aminotriazole a tué les tubercules fils déjà présents, alors que le glyphosate a affecté leur germina tion et par suite leur capacitéà produire de nouvelles plantes. La valeur pratique de ces deux herbicides pour lutter contre les repousses de pommes de terre est discutée. Die Wirkung von Gtyphosat und Aminotriazot auf Unkraut-Kar-toffelpflanzen und deren Tochterknollen In drei Versuchen wurden durch Glyphosat (1,0 kg/ha) und durch Aminotriazol (1,5 kg/ha) Unkraut-Kartoffeln abgetotet. Glyphosat (0,5 kg/ha) ergab unter Feldbedingungen eine brauchbare Bekampfung, nicht jedoch in zwei Gefassver-suchen; in letzteren wurde die Wirkung von Glyphosat durch den Zusatz von Ammoniumsulfat verbessert. Die Feldbehan-dlung Ende Mai war bei beiden Herbiziden weniger wirksam wie im Juni und Juli, weil im Mai das Kraut noch nicht voll entwickelt war. Durch Aminotriazol wurden alle bereits vor-handenen Tochterknollen getötet, wogegen Glyphosat das Kraut schädigte und damit auch die Bildung neuer Pflanzen beeinflusste. Es werden die Möglichkeiten diskutiert, die sich durch die beiden Herbizide für die Bekämpfung von Unkraut-Kartoffeln ergeben. 相似文献
16.
Experiments were conducted in a growth cabinet to investigate the absorption and translocation of 14C-3, 6-dichloropicolinic acid by Cirsium arvense (L.) Scop. (Canada thistle, creeping thistle), a sensitive species. Applications were made, either to the middle four leaves of 12-cm-tall vegetative plants grown under low (40%) and/or high (>95%) relative humidity (r.h.), or to four upper or lower leaves of 30-cm-tall flowering plants grown under low r.h. Following application to vegetative plants, absorption and translocation of 14C-3,6-dichloropicolinic acid was rapid and was approximately doubled by high r.h. High r.h. increased the amount of radioactivity retained by the treated leaves or translocated to the shoots but did not affect greatly the amount retained in the roots. The herbicide was highly mobile, with over half of that absorbed, translocated out of the treated leaves after two days. The apex accumulated most of the radioactivity, while approximately 8% was recovered from the roots. The absorption and translocation patterns were similar to those reported in the literature for picloram in C. arvense. Absorption of 3,6-dichloropicolinic acid was greater in vegetative than in flowering C. arvense plants, and placement of herbicide on lower leaves tended to decrease the amount of radioactivity recovered from shoot apex and increase the amount recovered from the roots. Approximately 15% of the applied radioactivity could not be recovered from treated plants by 2 days after treatment. 相似文献
17.
Irvin J. Belasco Jerry C-Y. Han Robert L. Chrzanowski Frederic J. Baude 《Pest management science》1981,12(4):355-364
Foliar-applied [14]cymoxanil, 1-(2-cyano-2-methoxyimino-[2-14C]acetyl)-3-ethylurea was rapidly metabolised in grapes, tomatoes and potatoes, Furthermore, the metabolism of this fungicide was unusual in that the metabolites were found to be naturally occurring compounds, with glycine as the major metabolite. Significant levels of radioactivity were found in other amino-acids, sugars, starch, fatty acids and lignin, indicating incorporation of carbon-14 via the various metabolic pathways. 相似文献
18.
Brenda S. Perkovich Todd A. Anderson Ellen L. Kruger Joel R. Coats 《Pest management science》1996,46(4):391-396
Mineralization of atrazine (6-chloro-N2-ethyl-N4-isopropyl-1,3,5- triazine-2,4-diamine) in soil treated with a mixture of atrazine and metolachlor (2-chloro-6′-ethyl-N-(2-methoxy-1-methylethyl)acet-o-toluidide at concentrations typical of point-source contamination (50 μg g−1 each) was significantly greater (P<0·001) in rhizospheric soil from Kochia scoparia (L.) Roth., a herbicide-resistant plant, than in non-vegetated and control soils. Soils were collected from an agrochemical dealership contaminated with several herbicides, including atra-zine, metolachlor, trifluralin (α,α,α-trifluoro-2,6-dinitro-N,N-dipropyl-p-toluidine and pendimethalin (N-(1-ethylpropyl)-2,6-dinitro-3,4-xylidene), at concentrations well exceeding the field application rates. Mineralization rates of ring-labeled atrazine in both rhizospheric and non-vegetated soils were quite high (>47% of the initial 14C applied after 36 days) compared to literature values. These results suggest that plants such as Kochia might be managed at pesticide-contaminated sites to help facilitate microbial degradation of wastes such as atrazine in soil. 相似文献
19.
Thomas W. Fuhremann E. Paul Lichtensteina Rainer N. Zahlten Frederick W. Stratman Heinrich K. Schnoes 《Pest management science》1974,5(1):31-39
Perfusion of 14C-(ring)-parathion or 14C-(ring)-paraoxon with blood through isolated, intact rat livers resulted in the rapid degradation of these insecticides. Degradation was negligible in the absence of rat liver (controls), thus demonstrating the capacity of the liver per se to effectively degrade these compounds. Of the total radiocarbon recovered after liver perfusion with [14C]parathion, 33 % could be attributed to unchanged [14C]parathion (similarly distributed between the liver and the blood) while 67.9 % was degraded to water soluble compounds and 2.5% was converted to organic soluble paraoxon and traces of p-nitrophenol. Nearly all of the [14C]paraoxon, however, was degraded by the intact rat liver, resulting in water soluble products that amounted to 98.5% of the total radiocarbon recovered. Unexplained losses of radiocarbon with the perfusion apparatus used were lower in the presence of rat liver which degraded the insecticides to more water soluble compounds. The water soluble degradation products produced from [14C]parathion and [14C]paraoxon were non-toxic to mosquito larvae (Aedes aegypti L.). These ring-labelled products were found to be conjugated p-nito-phenol. Nearly all of the water soluble radiocarbon was located in the perfused blood, while only small amounts (1.8 to 3.0% of recovered) were excreted via the bile or were associated with the liver tissue (1.3 to 1.8 % of recovered). 相似文献
20.
Absorption, translocation and distribution of 14C-glyphosate were examined in Agropyron repens (L.) Beauv. plants growing under field conditions in the autumn. Glyphosate absorption did not increase beyond 3 days after application, whereas translocation to the rhizomes continued up to 7 days after application. The translocated glyphosate accumulated more in new rhizomes than in older parts of the rhizomes. Ten per cent of the glyphosate translocated out of the treated shoot was recovered in younger shoots 7 days after application. Plants harvested the following spring contained less than 20% of the glyphosate originally applied. Although a growth cabinet experiment indicated that 34% of the glyphosate in the rhizomes of treated plants could be remobi-lized into new aerial shoots, considerably less was recovered in new, aerial shoots in the spring in the field-grown plants. Freezing experiments showed that glyphosate translocation to the rhizomes was only prevented when cold treatment caused visible damage to A. repens foliage. 相似文献