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1.
The pattern and extent of 14C-glyphosate [N-(phosphonomethyl)glycine] translocation from the treated leaf and metabolism of 14C-glyphosate were studied in field bindweed (Convolvulus arvensis L.), hedge bindweed (Convolvulus sepium L.). Canada thistle [Cirsium arvense (L.) Scop.] tall morning glory [lpomoea purpurea (L.) Roth.] and wild buckwheat (Polygonum convolvulus L.). 14C was translocated throughout the plants within 3 days with accumulation in the meristematic tips of the roots and shoots evident. Cross and longitudinal sections of stems and roots showed that the 14C was localized in the phloem. Field bindweed translocated 3–5% of the applied 14C from the treated leaf, hedge bindweed 21.6%, Canada thistle 7.8%, tall morningglory 6.5%, and wild buckwheat 5%. Field bindweed, Canada thistle, and tall morningglory metabolized the parent glyphosate to aminomethylphosphonic acid to a limited extent. This metabolite made up less than 15% of the total 14C. Of the total 14C applied to excised leaves, 50% had disappeared within 25 days. 相似文献
2.
A. J. SANAD 《Weed Research》1971,11(4):215-223
Studies of the uptake and translocation of 14C-labelled 2, 4-D, MCPA and aminotriazole in Agrostemma githago L. and Tussilago farfara L. clarified the behaviour of the herbicides in both species. In A. githago, MCPA was more freely mobile than 2,4-D after application to the leaf; it was distributed in the plant more rapidly and in greater quantity. Similarly, following root uptake MCPA was transported in the shoot in greater amounts than was 2,4-D. There is a clear relationship between the susceptibility of A. githago to MCPA and the mobility of the herbicide in the plant. In T. farfara, 2,4-D and aminotriazole applied to the leaves were equally well absorbed and relatively rapidly translocated. During the period up to 72 h the amounts of herbicide in the plant increased to similar levels; after that, 14C activity in plants treated with 2,4-D fell slightly whereas there was further accumulation of aminotriazole. Following uptake through the roots, translocation and accumulation in the leaves were considerably greater with aminotriazole than with 2,4-D. The lack of accumulation of 2,4-D could be a factor in the resistance of T. farfara to this herbicidie. Recherches sur l'absorption et la migration d'herbicides marqués au 14 C dans Agrostemma githago L. et Tussilago farfara L. 相似文献
3.
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
4.
Two populations of Hordeum leporinum have evolved resistance to paraquat within a small area in central Tasmania, Australia. One population (THL1) was more than 80-fold resistant to paraquat when treated in winter, compared with a susceptible population (THL4) collected nearby, whereas the other population (THL2) was only 19-fold resistant. Translocation of paraquat was examined in all three populations at warm and cool temperature regimes. Herbicide was applied to a basal section of the second leaf of plants kept in the dark and translocation measured after 16 h of dark and during a subsequent light period. Paraquat absorption into the treated leaf was uniformly high in susceptible and resistant populations, with >93% of the applied herbicide absorbed within 16 h in the dark at both temperatures. Translocation of paraquat out of the treated leaf was low in the dark, with <4% of the herbicide translocated to the remainder of the plant. More herbicide was translocated out of the treated leaves in susceptible plants in the dark, compared with resistant plants at both temperature regimes and more paraquat was translocated at warmer temperatures. Extensive basipetal translocation of paraquat to the rest of the plant occurred in susceptible plants following exposure of the treated plants to light. However, basipetal translocation was much reduced in resistant plants in the light and corresponded to the degree of resistance. Resistance to paraquat in H. leporinum is the result of reduced translocation of paraquat out of the treated leaves. 相似文献
5.
Control of Avena fatua (L.) (wild oat) with diclofop methyl applied at 0·7 kg ha?1 at the two-leaf stage and difenzoquat at 0·84 kg ha?1 at the four-leaf stage in wheat (Triticum aestivum L.) under field conditions was good and not affected when either of these herbicides was mixed with 3,6-dichloropicolinic acid as the monoethanolamine salt at 0·14, 0·20 or 0·30 kg ha?1. In the glasshouse, mixtures containing 3,6-dichloropicolinic acid at rates as high as 0·6 kg ha?1 also did not affect control of A. fatua. When barban at 0·35 kg ha?1, or flamprop methyl at 0·56 kg ha?1 was mixed with similar rates of 3,6-dichloropicolinic acid and applied at the two-leaf and four-leaf stage of A. fatua respectively, a reduction in control of A. fatua (antagonism) occurred under both field and glasshouse conditions. The herbicides for control of A. fatua did not influence the fresh weight suppression of C. arvense shoots obtained in the glasshouse with 3,6-dichloropico-colinic acid at 0·3 kg ha?1. Early tolerance of wheat (cv. Neepawa) was acceptable with all mixtures. Wheat yields with diclofop methyl or difenzoquat alone or in mixture with 3,6-dichloropicolinic acid were increased over the yields from the A. fatua-infested control. 相似文献
6.
Scott J. Nissen Robert A. Masters W. Mack Thompson Robert N. Stougaard 《Pest management science》1995,45(4):325-329
Imazapyr absorption, translocation, root release and metabolism were examined in leafy spurge (Euphorbia esula L.). Leafy spurge plants were propagated from root cuttings and [14C]imazapyr was applied to growth-chambergrown plants in a water + 28% urea ammonium nitrate + nonionic surfactant solution (98.75 + 1 + 0.25 by volume). Plants were harvested two and eight days after herbicide treatment (DAT) and divided into: treated leaf, stem and leaves above treated leaf, stem and leaves below the treated leaf, crown, root, dormant and elongated adventitious shoot buds. Imazapyr absorption increased from 62.5% 2 DAT to 80.0% 8 DAT. Herbicide translocation out of the treated leaf and accumulation in roots and adventitious shoot buds was apparent 2 DAT. By the end of the eight-day translocation period only 14% of applied 14C remained in the treated leaf, while 17% had translocated into the root system. Elongated and dormant adventitious shoot buds accumulated 3.2- and 1.8-fold more 14C, respectively, 8 DAT than did root tissue based on Bq g?1 dry weight. Root release of 14C was evident 2 DAT, and by 8 DAT 19.4% of the 14C reaching the root system was released into the rooting medium. There was no metabolism of imazapyr in crown, root or adventitious shoot buds 2 DAT; however, imazapyr metabolism was evident in the treated leaf 2 and 8 DAT. Imazapyr phytotoxicity to leafy spurge appears to result from high imazapyr absorption, translocation to underground meristematic areas (roots and adventitious shoot buds), and a slow rate of metabolism. 相似文献
7.
In controlled environmental studies, a marked difference was observed between the growth pattern of tomato and eastern black nightshade plants that received doses of 2,4-D ranging from 28 to 952 g a.e. ha?1. The highest dose of 2,4-D reduced the dry weight of eastern black nightshade and tomato by approximately 15 and 50%, respectively, when compared with controls. Although the height of both species was reduced by all doses of 2,4-D, eastern black nightshade plants produced secondary shoots, which compensated for any potential loss in dry weight that otherwise may have occurred. Tomato plants did not produce secondary shoots. After application of 14C-2,4-D to tomato and eastern black nightshade, the pattern of 14C absorption and translocation was similar in both plant species. However, there was significantly more radioactivity recovered in tomato (72%) than in eastern black nightshade (52%) plants, 72 h after treatment. Assay radioactivity in the nutrient solution of hydroponically grown plants indicated that 7·0 and 27·9% of the applied radioactivity was exuded from the roots of tomato and eastern black nightshade, respectively, within 72 h after treatment. Assay of plant extracts by thin layer chromatography revealed that the amount of radioactivity that remained as unaltered 2,4-D was 73 and 49% in tomato and eastern black nightshade, respectively, 72 h after treatment. Thus the greater tolerance of eastern black nightshade appeared to be due to greater rates of 2,4-D metabolism and/or greater rates of herbicide elimination by root exudation. 相似文献
8.
The metabolic fate of the 14C-labeled herbicide, 2-(3,4-dichlorophenyl)-4-methyl-1,2,4-oxadiazolidine-3,5-dione (bioxone), in cotton (Gossypium hirsutum L. “Acala 4-42-77”) was studied using thin-layer chromatography, autoradiography, and counting. Bioxone-14C was readily metabolized by cotton tissue to 1-(3,4-dichlorophenyl)-3-methylurea (DCPMU) and 1-(3,4-dichlorophenyl)urea (DCPU). Leaf discs metabolized bioxone-14C rapidly; 12 hr posttreatment, 65% of the 14C in methanol extracts was in forms other than intact herbicide. Excised leaves treated through the petiole with either heterocyclic ring-labeled or phenyl ring-labeled herbicide contained little bioxone-14C after 1 day; DCPMU was formed early then decreased with time. DCPU accounted for 55–70% of the 14C in excised leaves 3 days posttreatment. In intact plants treated via the roots, the herbicide was rapidly metabolized in the roots to DCPMU and DCPU; little or no intact herbicide was translocated to the leaves. Little radioactivity accumulated in the roots with time; the radioactivity in the leaves accounted for 80–90% of the methanol-soluble 14C 47 days posttreatment. Most of the 14C in the leaves was recovered as DCPU (50–60%) and unidentified polar metabolite(s) which remained at the origin of the thin-layer plates (30–40%). The percentage of radioactivity which remained in cotton residue after methanol extraction increased with time. Digestion of the plant residues with the proteolytic enzyme pronase indicated that some of the nonextractable 14C may be DCPMU and DCPU complexed with proteins. Similar metabolic patterns were noted after treatment with either heterocyclic ring-labeled or phenyl ring-labeled bioxone-14C. Generally, bioxone was metabolized to DCPMU which in turn was demethylated to DCPU. The herbicide and DCPMU were 20 times as toxic as DCPU to oat (Avena sativa L.), a susceptible species. 相似文献
9.
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
10.
Experiments were conducted to examine the up take, translocation and metabolism by S. vulgaris of two distinctly different herbicides: 2,4-D, a phenoxyalkanoic acid with growth regulator activity to which this species exhibits complete tolerance, and chlorsulfuron, a sul-fonylurea to which S. vulgaris is highly sensitive. Despite their structural dissimilarities 2,4-D and chlorsulfuron was readily absorbed by S. vulgaris with 65 and 69%, respectively, of the applied dosage being absorbed within 72 hours after treatment. Approximately 35% of the 2,4-D and 10% of the chlorsulfuron label was translocated out of the treated leaf after 72 hours. Neither herbicide accumulated in the terminal bud. Seventy-two hours after treatment 63% of the recovered 14C remained as unaltered 2,4-D in S. vulgaris, while in tomato, a 2,4-D sensitive species, 65% of the recovered 14C remained as intact herbicide. In S. vulgaris approximately 86% of the radioactivity remained as intact chlorsulfuron 72 hours after treatment compared to 12% in the tolerant wheat. The tolerance of S. vulgaris to 2,4-D could not be accounted for by limited absorption, translocation nor metabolic degradation of the herbicide. The sensitivity of S. vulgaris to chlorsulfuron would appear to be related to the inability of this species to metabolize the herbicide molecule. 相似文献
11.
The dose-response, foliar uptake, translocation and metabolism of the methylheptyl ester (MHE) of fluroxypyr were examined in lambs-quarters (Chenopodium album L.), wild buckwheat (Polygonum convolvulus L.), Canada thistle (Cirsium arvense L. Scop.) and field bindweed (Convolvulus arvensis L.). Under controlled environment growth room conditions, E50 values, determined from shoot dry weights of the susceptible species, wild buckwheat (16 g ha?1) and field bindweed (40 g ha?1), were markedly different than those of the tolerant species, lambsquarters (331 g ha?1) and Canada thistle (800 g ha?1). Regardless of species, more than 80% of applied [14C]fluroxypyr-MHE was absorbed by foliar surfaces 120 h after treatment. Translocation of radioactivity out of the treated leaves of susceptible species was significantly greater than that of tolerant species. For example, 120 h after treatment with [14C]-fluroxypyr-MHE, the proportion of applied radioactivity translocated in tolerant Canada thistle and lambsquarters was 15 and 10%, respectively, whereas in susceptible wild buckwheat and field bindweed it was 41 and 40% of applied radioactivity, respectively. High-performance liquid chromatography (HPLC) of plant extracts indicated four distinct chroma-tographic peaks common to all four species. More fluroxypyr was recovered in the susceptible species (70%) than in the tolerant species (30%), 120 h after application. Selectivity differences between the tolerant and susceptible species may be the result of enhanced metabolic transformation of the herbicide to more polar, non-phytotoxic compounds with limited mobility within the tolerant species. Les bases de la sélectivité du fluroxypyr La courbe dose effet, la pénétration foliaire, la migration et le métabolisme de Tester méthyle-heptyle (MHE) du fluroxypyr ont étéétudiés chez le chénopode blanc (Chenopodium album L.), la renouée faux-liseron (Polygonum con-vulvulus L.), le chardon des champs (Cirsium arvense L. Scop.) et le liseron des champs (Convolvulus arvensis L.). En conditions de crois-sance contrôlées, les valeurs ED50, déterminées à partir du poids de matière sèche des parties aériennes étaient nettement différentes chez les plantes sensibles et chez les plantes résistan-tes:renouée faux-liseron, 16 g ha?1; liseron des champs, 40 g ha?1; chénopode blanc, 331 g ha?1; chardon des champs, 800 g ha?1. Quelle que soit 1'espèce, plus de 80% du [14C]fluroxypyr-MHE pénétrait dans les feuilles en 120 h. La migration de la radioactivité hors des feuilles traitérs était significativement plus importante chez les plantes sensibles que chez les plantes tolérantes. Par exemple, 120 h après le traite-ment avec du [14C]fluroxypyr-MHE, la proportion de radioactivité appliquée qui avait migré dans le chardon des champs et le chénopode, tolérants, était respectivement 15 et 10%, alors que chez la renouée faux-liseron et le liseron des champs, sensibles, elle était respectivement 41 et 40%. Des analyses par HPLC des extraits de plantes montraient quatre pics chro-matographiques distincts dans chacune des quatre espèces. Davantage de fluroxypyr était retrouvé 120 h après 1'application chez les plantes sensibles que chez les plantes résistantes (70% contre 30%). Les différences de sensibilité entre espèces pourraient être dues chez les plantes tolérantes à un métabolisme plus important de l'herbicide en composés plus polaires, non phytotoxiques et peu mobiles. Grundlagen für die selektive Wirkung von Fluroxypyr Die Dosis/Wirkungs-Beziehung, Blattaufnahme, Translokation und Metabolismus des Methylheptyl-Esters (MHE) von Fluroxypyr wurden bei Weißem Gänsefuß (Chenopodium album L.), Gemeinem Windenknöterich (Polygonum convolvulus L.), Acker-Kratzdistel (Cirsium arvense (L.) Scop.) und Gemeiner Ackerwinde (Convolvulus arvensis L.) untersucht. Unter den kontrollierten Umweltbedingungen eines Phytotrons wurden anhand des Trockengewichts die ED50-Werte bestimmt, die bei den empfindlichen Arten Polygonum convolvulus mit 16 g ha?1 und Convolvulus arvensis mit 40 g ha?1 sich deutlich von denen der toleranten Arten Chenopodium album mit 331 g ha?1 und Cirsium arvense mit 800 g ha?1 unterschieden. Unabhängig von der Art waren mehr als 80 % der Aufwandmenge von [14C]-Fluroxypyr-MHE durch die Blattoberflächen 120 h nach der Behandlung aufgenommen. Die Translokation der Radioaktivität aus den behandelten Blättern war bei den empfindlichen Arten signifikant größer als bei den toleranten. Z. B. waren 120 h nach der Behandlung bei den toleranten Arten Cirsium arvense und Chenopodium album 15 bzw. 10 % der Radioaktivität transloziert, während es bei den empfindlichen Arten Polygonum convolvulus und Convolvulus arvensis 41 bzw. 40 % waren. Bei allen 4 Arten ergab eine HPLC-Untersuchung der Pflanzenextrakte 4 distinkte Peaks. Bei den empfindlichen Arten wurde 120 h nach der Anwendung mit 70 % mehr Fluroxypyr wiedergefunden als bei den toleranten (30 %). Die Selektivitätsunterschiede zwischen den toleranten und empfindlichen Arten könnten auf einen beschleunigten Metabolismus des Herbizids zu stärker polaren, nichphytotoxischen Stoffen mit eingeschränkter Mobilität bei den toleranten Arten zurückgeführt werden. 相似文献
12.
Summary. Detached leaves treated with 2,4-DB were used to demonstrate that the foliage of Acer macrophyllum Pursh. possesses the enzyme systems necessary for oxidation of the 2,4-DB side chain. Absorption and translocation studies showed that 2,4-DB was absorbed less but translocated more than some other phenoxy herbicides which have been tested on this species. Studies with excised stem phloem and excised roots showed that different plant tissues are not equally capable of decarboxylating 2,4-DB. An experiment with intact plants established that 2,4-DB was translocated unchanged, and that the primary product of the oxidation of 2,4-DB is 2,4-D. The results are discussed with respect to the translocation characteristics of this herbicide in bigleaf maple. Caractères de l'absorption, de la migration et du métabolisme de l'acide 4-(2,4-dichlorophénoxy) butyrique dans l'érable a grandes feuilles 相似文献
13.
The uptake and translocation of 14C-labelled ethofumesate [(±)-2-ethoxy-2,3-dihydro-3,3-dimethylbenzofuran-5-yl methanesulphonate] was studied in sugar-beet seedlings following soil and foliar applications. After soil applications, the roots absorbed and translocated to the foliage more ethofumesate or its metabolites than did the emerging hypocotyls. Ethofumesate or its metabolites did not accumulate in either roots or hypocotyls after exposure to treated soil. When sugar-beet leaves were treated with the herbicide at the two-leaf stage, acropetal translocation was rapid but there was no translocation out of the treated leaves. Furthermore, ethofumesate or its metabolites were not translocated basipetally after either soil or foliar application. 相似文献
14.
Mechanism of resistance to bensulfuron-methyl in Alisma plantago-aquatica biotypes from Portuguese rice paddy fields 总被引：1，自引：0，他引：1
Two Alisma plantago‐aquatica biotypes resistant to bensulfuron‐methyl were detected in rice paddy fields in Portugal’s Mondego (biotype T) and Tagus and Sorraia (biotype Q) River valleys. The fields had been treated with bensulfuron‐methyl‐based herbicide mixtures for 4–6 years. In order to characterize the resistant (R) biotypes, dose–response experiments, absorption and translocation assays, metabolism studies and acetolactate synthase (ALS) activity assays were performed. There were marked differences between R and susceptible (S) biotypes, with a resistance index (ED50R/S) of 500 and 6.25 for biotypes Q and T respectively. Cross‐resistance to azimsulfuron, cinosulfuron and ethoxysulfuron, but not to metsulfuron‐methyl, imazethapyr, bentazone, propanil and MCPA was demonstrated. No differences in the absorption and translocation of 14C‐bensulfuron‐methyl were found between the biotypes studied. Maximum absorption attained 1.12, 2.02 and 2.56 nmol g−1 dry weight after 96 h incubation with herbicide, for S, Q and T biotypes respectively. Most of the radioactivity taken up by the roots was translocated to shoots. Bensulfuron‐methyl metabolism in shoots was similar in all biotypes. The R biotypes displayed a higher level of ALS activity than the S biotype, both in the presence and absence of herbicide and the resistance indices (IC50R/S) were 20 197 and 10 for biotypes Q and T respectively. These data confirm for the first time that resistance to bensulfuron‐methyl in A. plantago‐aquatica is target‐site‐based. In practice, to control target site R biotypes, it would be preferable to use mixtures of ALS inhibitors with herbicides with other modes of action. 相似文献
15.
A F M Silva G S Silva K F Mendes A L Giraldeli V L Tornisielo R Victoria Filho 《Weed Research》2019,59(1):58-66
Members of the Convolvulaceae family are known to be sensitive to aminocyclopyrachlor, although little is known about the absorption, translocation and metabolism of the herbicide in these species of weed. The aim of this study was to evaluate the absorption, translocation and metabolism of 14C‐aminocyclopyrachlor in young plants of Ipomoea purpurea and Ipomoea triloba. Assessments were performed at 3, 6, 12, 24, 48 and 72 h after treatment (HAT) for the study of absorption and translocation. Metabolism was assessed at three time points (3, 24 and 72 HAT). In terms of absorption, was observed a difference between species at the 3 and 48 HAT time points, where I. purpurea had a higher absorption of 14C‐aminocyclopyrachlor. No differences were observed between species at any other time points. Of the total absorbed herbicide, 90.9% for I. purpurea and 91.8% for I. triloba were detected on the treated leaf. I. purpurea presented higher translocation to the leaf above the treated leaf, while I. triloba showed higher translocation to the lower leaves and roots. No increase in absorption of 14C‐aminocyclopyrachlor was observed above 24 HAT for I. purpurea and above 6 HAT for I. triloba, and translocation was low (<1%) for both species in all plant parts. This suggests that post‐emergence application of aminocyclopyrachlor cannot be effective for the control of I. purpurea and I. triloba and alternative approaches are required. Nevertheless, no 14C‐aminocyclopyrachlor metabolites were observed in the studied plants, which indicated sensitivity in I. purpurea and I. triloba to the herbicide. 相似文献
16.
W. MERSIE 《Weed Research》1995,35(1):15-18
Witloof chicory (Cichorium intybus L.) is tolerant to propyzamide and common amaranth (Amaranthus retroflexus L.) is sensitive. The absorption, translocation, and metabolism of propyzamide was studied in seedlings of witloof chicory and common amaranth to determine if differences in these processes cause the differential sensitivity. At 24,48, and 72 h after root treatment, there was no difference in the concentration of 14C (g?1 plant dry wt) in com-mon amaranth and witloof chicory. Approximately 50% of the absorbed 14C was translocated out of the roots to shoots of both species at 24 and 48 h after treatment. After 72 h about 55 and 74% of the absorbed 14C was translocated to shoots of witloof chicory and common amaranth, respectively. Distribution of 14C (g?1 plant dry wt) in plant parts of witloof chicory and common amaranth seedlings was similar. Roots of both species accumulated the highest concentration of total 14C, whereas shoots contained the lowest. Thin layer chromatography revealed that the herbicide was metabolized in neither species 48 h after treatment. No differences were found in absorption, translocation, or metabolism between witloof chicory and common amaranth with regard to propyzamide. 相似文献
17.
Absorption and translocation of glyphosate in Spermacoce verticillata and alternative herbicide control 
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下载免费PDF全文 D A Fadin V L Tornisielo A A M Barroso S Ramos F C Dos Reis P A Monquero 《Weed Research》2018,58(5):389-396
Glyphosate has been associated with control failures for Spermacoce verticillata in some Brazilian States. The objective of this work was to evaluate and determine the possible causes of this and propose alternative herbicides to use. Glyphosate was applied at three plant stages of development (2–4 leaves, 4–6 leaves and full bloom) where foliar absorption and translocation of glyphosate to various plants parts and time were analysed using the 14C technique. Data were submitted to nonlinear regressions and analysis of variance, where means were compared by a Tukey test at 5% probability. Plant control by the application of different herbicides (19) in the same three stages of development of weed was evaluated. Twenty‐one days after herbicide application, control was visually evaluated and data analysed and means were compared. Due to absorption and/or translocation problems, S. verticillata plants were not controlled by glyphosate. Plants with 4–6 leaves showed lower absorption and translocation of the herbicide to the leaf/root regions compared with plants at the beginning of their development. Plants at full bloom showed lower translocation of the herbicide to the root. In addition to the application of glyphosate at early stages of development, the application of paraquat, flumioxazin and mixtures of glyphosate with flumioxazin or cloransulam is recommended. Late applications could result in poor control, principally if glyphosate is used. Therefore, early applications are strongly recommended for control of this species. 相似文献
18.
Studies of the absorption and translocation of 14C-2,4-D in Chenopodium album L., Galinsoga parviflora Cav., Datura stramonium L. and Galium aparine L. in relation to their susceptibility gave the following results: In G aparine (resistant) there was little transport of 2,4-D applied to the leaves, and a probable relationship between resistance and the immediate binding of the 2,4-D in the treated leaf. D. stramonium (relatively resistant) transported 2,4-D in considerable amounts alter uptake through the leaf, while C. album (very susceptible) and G. parviflora (susceptible) were intermediate in respect of 2,4-D translocation. No relationship between susceptibility of these four species and 2,4-D uptake and translocation from the leaves could be established. After application to the root systems of the four species, 2,4-D was taken up and translocated in the shoot to varying extents. In G. aparine much 2,4-D was taken up and translocated. In contrast to leaf application, the herbicide was not immediately converted into a strongly-held immobile form. In C. album, G. parviflora and D. stramonium, however, no 2,4-D was translocated in the shoot. There was thus no correlation between susceptibility and shoot transport of 2,4-D in the four species studied. Distribution du 2,4-D marqué au 14C dans des espèces de mauvaises herbes présentant des sensibilités diverses 相似文献
19.
Growth chamber experiments were conducted in order to study the absorption, translocation and activity of glyphosate when applied to roots with aqueous solution avoiding any glyphosate–substrate interaction. Corn seedlings at the first leaf stage were set up in individual graduated cylinders containing different solutions of 14 C-glyphosate (0–30 mg ae kg−1 ). After 26 h of root exposure, plants were transferred to fresh nutrient solution and grown for the next 5 days. After harvest, plants were separated into seed, root, mesocotyle, coleoptile, cotyledon, first leaf and all new leaves (apex), and quantified 14 C radioactivity contained in each part. Glyphosate uptake was only 11% of the theoretical mass flow into the plant. The amount of glyphosate translocated from roots was positively correlated with plant uptake ( P < 0.01). Total plant fresh weight presented a logistic response to glyphosate amounts, including a growth stimulant effect (hormesis), when plants absorbed less than 0.6 µg. The treated plants presented a normal pattern of glyphosate allocation, with the apex the principal sink, accumulating more than 38% of mobilized glyphosate. When corn plants absorbed more than 0.6 µg they showed a decrease in growth. The relatively high glyphosate quantities allocated in the new leaves showed the relevance of the symplastic pathway in the translocation process for root absorbed glyphosate. 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