Uptake and phytotoxicity of chlorsulfuron in Zea mays L. in the presence of 1,8-naphthalic anhydride

The sites of uptake of chlorsulfuron in maize (Zea mays L.) were investigated at three different growth stages. Exposure of seedling roots, or shoots separately, to herbicide-treated sand over 4 days resulted in inhibition of both roots and shoots. Exposure of seedling roots to chlorsulfuron-treated soil over 21 days severely inhibited both roots and foliage, while separate shoot exposure also reduced both foliage and root growth. After plant emergence, exposure of the crown root node, growing point and lower stem to treated soil reduced foliage and root growth, but exposure of the shoot above the growing point caused only slight inhibition of foliage and had no effect on roots. The herbicide safener 1,8-naphthalic anhydride (NA) applied as a dust (10 g kg^?1 seed weight), or as a 50 mg 1^?1 suspension in water to maize seeds, reduced the root inhibition by chlorsulfuron in 4-day-old seedlings. NA completely prevented both foliage and root injury when chlorsulfuron was placed in soil in the shoot zone before emergence, or in the shoot zone below the soil surface after plant emergence. NA slightly decreased injury to foliage, but not to roots when chlorsulfuron was placed in soil in the root zone before emergence. NA seed treatment protected both roots and foliage against injury from foliarly applied chlorsulfuron. Plants were also protected when a suspension of NA in water was sprayed on the foliage seven days before chlorsulfuron. When a mixture of NA and chlorsulfuron was applied to foliage, root injury was reduced more than foliage injury.     

Uptake, translocation and phytotoxicity of imazapyr and glyphosate in Imperata cylindrica (L.) Raeuschel: effect of herbicide concentration, position of deposit and two methods of direct contact application

The activity of imazapyr and glyphosate against Imperata cylindrica was studied in field and glasshouse experiments using two methods of direct contact application; a rope-wick wiper and a cloth soaked in herbicide solution. The effect of concentration and position of application on herbicide uptake and translocation was also measured. At the lowest dose of imazapyr (5 mg acid equivalent (a.e.) per plant), phytotoxicity was greater from applications by a rope-wick wiper than by a cloth. However, when the dose of imazapyr was increased, the cloth applicator was more effective than the rope-wick wiper. At all doses of glyphosate, rope-wick application was more effective than wiping with a cloth. Herbicide performance in the glasshouse was similar to that in the field. Radiotracer studies showed that increasing the concentration of imazapyr, while keeping herbicide dose constant, decreased uptake and translocation of radiolabel. In contrast, the rate of uptake of ¹⁴C-glyphosate increased with increasing herbicide concentration. Position of application did not significantly affect the amount of uptake and translocation of radiolabel to the rhizomes. It is concluded that rope-wick wipers are more effective than wiping with a cloth for applying imazapyr and glyphosate to I. cylindrica, provided that the concentration of imazapyr does not exceed 10 g a.e. l^?1.     

Uptake and translocation of carpropamid in rice (Oryza sativa L)

Translocation of the antiblast compound, carpropamid, was investigated in rice using [¹⁴C]carpropamid. When applied to the seed, carpropamid was not only readily absorbed but was translocated to different parts of the seedlings emerging from treated seeds. A substantial portion of fungicide appeared to be exuded onto the leaf surface. In 21‐day‐old plants grown from [¹⁴C]carpropamid‐treated seeds, 27.2% of the radioactivity isolated from leaves was present on the surface of lamina. This exuded fraction is probably responsible for its action as a fungal anti‐penetrant compound. Following 30‐min root dipping of 14‐day‐old seedlings, carpropamid was rapidly absorbed and translocated throughout the seedling. Its intra‐laminar distribution was uniform as determined by autoradiography. Only a small fraction (<2%) of fungicide applied to the foliage was translocated beyond the site of application within the treated leaf. Translocation was primarily apoplastic. Approximately 54% of the radioactivity recovered from leaves was in the form of carpropamid. At least seven radiolabelled metabolic products were observed by TLC. Only 8.3% of radioactivity applied through the seeds could be recovered from 21‐day‐old seedlings. © 2001 Society of Chemical Industry     

Joint action of root-absorbed mixtures of auxin herbicides in Sinapis alba L. and barley (Hordeum vulgare L.)

The efficacy of some binary mixtures of MCPA, 2,4-D dichlorprop, mecoprop and dicamba was evaluated in water culture experiments. Within each of seven assays, two dose-response curves described the phytotoxicity of the herbicides administered separately and three curves described the phytotoxicity of mixtures in fixed ratios. A non-linear regression model of dry matter on the logarithm of the dose, assuming the five response curves to be mutually parallel, was fitted and a reference model, the Additive Dose Model (ADM) to assess the efficacy of the mixtures, was also incorporated into the regression. The biological interpretation of ADM is often associated with mixtures of compounds having similar mode of action. Mixtures of dicamba with dichlorprop or 2,4-D were more potent than expected under ADM in two Sinapis alba assays. In one assay with mixtures of MCPA and dichlorprop the parallel-line model fitted somewhat better than did the ADM regression. This also applied to a barley assay with mixtures of dicamba and MCPA. On the basis of the results obtained it is suggested that the analogy between the implicit assumptions of the parallel-line assay can be extended to the ADM. Parallel dose response curves are a necessary but not a sufficient condition for assuming similar mode of action Similarly, it can be argued that mixtures of compounds following ADM are a necessary but not a sufficient condition for assuming a similar mode of action for the herbicides in a mixture.     

吡虫啉在生菜中的吸收迁移及转化行为

为了探究吡虫啉在植物中的吸收转运规律,本研究选择生菜为研究对象,将其在含有1 mg/kg吡虫啉的水培液中持续暴露120 h,利用超高效液相色谱-三重四极杆质谱检测吡虫啉及其5种代谢物在生菜不同部位动态吸收变化和转运分布规律.结果表明,吡虫啉在叶部富集程度明显高于根部,当达到吸收稳定状态时,吡虫啉在叶部富集程度约为根部的...     

Joint action of root-absorbed mixtures of DPX-4189* and linuron in Sinapis alba L. and barley

The joint action of DPX-4189* (2 chloro-N-[(4-methoxy-6-methyl-1, 3, 5-triazin-2-yl)-aminocarbonyl] benzenesulfonamide) and linuron (N-[3, 4-dichlorophenyl]-N-methoxy-N-methylurea) mixtures, applied in fixed ratios of 1:15 and 1:30, was assessed using water culture experiments in growth chambers. The dose-response curves of DPX-4189 were fiat compared with these of linuron. At Gr₅₀-level (the dose required to reduce dry matter by 50% relative to the untreated control), DPX-4189 was 12-fold more potent in Sinapis alba than was linuron, whereas the potencies of the two compounds were almost similar in barley. The selectivity indices (Gr₈₀[barley]/Gr₂₀[S. alba]) of DPX-4189 and linuron were 3.1 and 1.8. In both species the mixtures were less active than expected from an additive dose model, and the detracted efficacy of the mixtures was of almost similar magnitude. The results indicated that if S. alba is regarded a weed, the loss of bioactivity of the mixtures may be compensated by some increase in dose rate without injuring the barley crop.     

Joint action of some root-absorbed herbicides in oats (Avena sativa L.)

In growth chambers the phytotoxicity of binary mixtures of four herbicides was compared using an Additive Dose Model as reference. Of the four herbicides used, lenacil was the most potent whereas ethofumesate was the least potent herbicide; chloridazon and metamitron were equally potent. The Additive Dose Model implicitly presupposes that at any one response level the herbicides of a mixture can replace each other in proportion to their relative potency when applied separately. Metamitron and chloridazon mixtures appeared to follow the reference model. The efficacy of mixtures of lenacil and chloridazon or lenacil and metamitron, however, were increased in comparison with the herbicides applied separately. On the other hand, lenacil and ethofumesate or metamitron and ethofumesate were less phytotoxic than expected from the Additive Dose Model. The results are discussed in relation to the mode of action of the compounds. Action combinée de certains herbicides absorbés par les racines en culture d'avoine Avena sativa L. La phytotoxicité de mélanges binaires de quatre herbicides a fait l'objet d'une comparaison en phytotron, utilisant comme témoin un Modèle Dose Additive. Parmi les quatre herbicides utilisés, le lénacile s'est révélé le plus et l'éthofumésate le moins actif; le chloridazone et le métamitrone ont fait preuve d'une activitéégale. Le Modèle Dose Additive présuppose qu'à tout niveau d'activité chaque herbicide faisant partie d'un mélange puisse se substituer à l'autre en fonction de son efficacité relative en traitement simple. Les mélanges métamitrone–chloridazone semblent s'accorder au modèle de référence. Cependant, l'efficacité des mélanges chloridazone–lénacile et lénacile–métamitrone a augmenté par rapport à l'application de chaque élément séparément. D'autre part, les mélanges lénacile–éthofumesate et métamitrone–éthofumesate ont fait preuve d'une phytotoxicité moindre que celle qu'annonçait le modèle. Ces résultats sont discutés par rapport au mode d'action des composés. Kombinierte Wirkung verschiedener wurzelwirksamer Herbizide auf Avena sativa L. In Klimakammern wurde die Phytotoxizität von Zweier-Mischungen von vier Herbiziden untersucht und mit einem Modell additiver Dosierungen verglichen. Von den vier untersuchten Herbiziden war Lenacil das wirksamste und Ethofumesat das schwächste; Chloridazon und Metamitron wirkten gleich stark. Das Modell additiver Dosierungen setzt stillschweigend voraus, dass auf jedem Wirkungsniveau die Herbizide einer Mischung einander im Verhältnis ihrer relativen Wirksamkeiten, wenn allein appliziert, ersetzen können. Metamitron + Chloridazon Mischungen scheinen dem Vergleichsmodell zu folgen. Die Wirkungen der Mischungen von Lenacil + Chloridazon oder Lenacil + Metamitron, hingegen, waren im Vergleich zu den Effekten der einzeln applizierten Komponenten gesteigert. Andrerseits waren Lenacil + Ethofumesat oder Metamitron + Ethofumesat weniger phytotoxisch, als das Modell hätte erwarten lassen. Die Resultate werden mit Bezug auf die Wirkungsmechanismen der Komponenten diskutiert.     

Uptake, translocation and bioavailability of imidacloprid in several hop varieties

The neonicotinoid insecticide imidacloprid is the most important insecticide in hop cultivation in Germany. A laboratory study was undertaken to investigate its systemic properties and translaminar bioavailability in hop leaves. Radiolabelled [methylene-14C]imidacloprid was applied either alone or in combination with different additives onto leaves of several hop varieties. Uptake and translocation were evaluated 1 and 7 days after foliar application under greenhouse conditions. The uptake of imidacloprid into hop leaves was most pronounced in the first 24 h after application and only negligible amounts were taken up after this period. Significant differences in the quantitative uptake occurred when imidacloprid was combined with additives, such as Amulsol, Genapol C-100, Hasten and LI 700. The uptake of imidacloprid applied without additives was less than 10% 7 days after application, whereas the combination with LI 700 provided 70-80% uptake. Genapol C-100 and Amulsol induced considerable phytotoxicity at the application site. Comparing hop varieties revealed differences up to twofold in foliar penetration of imidacloprid. The translaminar and acropetal bioavailability of imidacloprid foliarly applied to hop leaves was determined by a laboratory bioassay using the damson hop aphid, Phorodon humuli (Schrank). Significantly higher mortality was observed with laboratory formulations containing imidacloprid and the additive LI 700. In contrast to these results from systemic tests, contact mortality at the application site was constantly high over the testing period of 7 days, highlighting the importance of this mode of entry for aphid intoxication.     

Uptake and translocation of ethofumesate in sugar-beet plants

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.     

Influence of water stress on absorption, translocation and phytotoxicity of fenoxaprop-ethyl and imazamethabenz-methyl in Avena fatua

The influence of water stress on the absorption and translocation of ¹⁴C-labelled fenoxapropethyl and imazamthabenz-methyl in Avena fatua L. (wild oat) was studied. The phytoioxicity to A. fatua of both herbicides with a droplet application was also examined under water stress conditions. The absorption of both fenoxaproethyl and imazamethabenz-methyl was reduced by waler stress when the plants were harvested within 24 h after herbicide application. Up to 48 h after the application, the translocation out of the treated lamina of both herbicides, based on percentage of applied ¹⁴C. was reduced under water stress conditions. When havested 96 h after herbicide application, however, water stress no longer significantly affeaed the absorption and translocation of either herbicide. When the herbicides were applied as individual droplets, water stress reduced the phytotoxicity of fenoxaprop-ethyl but not that of imazamethabenz-methyl. It is concluded that the changes in herbieide absorption and translocation may not be the major physiological processes associated with differential whole-plant response oi A faiua to fenoxaprop-ethyl and imazamefhabenz-methyl under water stress.     

Uptake and translocation of dimefox and schradan in hops

During the 1971 growing season an experiment was carried out to study the uptake, translocation and residue levels of dimefox and schradan in hope after applying a soil drench of Terra-Sytarn (222 g/litre dimefox-20 g/litre schradan) at various times in varying concentrations. Residue analysis shows that the dimefox concentration in the hop plants reaches a peak about one week after application, which increases with the amount applied. Then a gradual breakdown sets in so that at the time of harvesting the differences between the dosages have virtually disappeared. Translocation of dimefox in the hop plant is very rapid, but the breakdown is faster at the top of the plant. Schradan concentrations were usually very low and residues at harvest time negligible.     

Uptake,translocation and metabolism of the herbicide molinate in tobacco and rice

Molinate, a selective herbicide, is used for the control of annual and perennial weeds in rice paddy fields. This study was designed to assess the basis of the selective action of molinate between a susceptible broadleaf crop, tobacco, and a resistant graminaceous plant, rice. Experiments were conducted comparing plant growth under different concentrations of molinate, determining the absorption and translocation of the herbicide in the plant and identifying the metabolites in suspension cells. Rice showed greater tolerance to molinate than tobacco. Leaves of tobacco showed retarded and distorted growth at 10 mg liter^-1 of molinate 14 days after treatment, but rice leaves were unaffected at this concentration. Higher concentrations of molinate accumulating in the root of tobacco seedlings may inhibit root development and represent a significant factor in the herbicide's selective action. Seven and eight metabolites were found in tobacco and rice cells, respectively, with molinate sulfoxide and molinate sulfone present in both species. © 1998 SCI     

Spray application factors and plant growth regulator performance: III. Interaction of daminozide uptake,translocation and phytotoxicity in bean seedlings

Effects of droplet size and carrier volume on foliar uptake and transport of daminozide were investigated. A constant dose of daminozide (100 µg per leaf) was applied to both primary leaves of 10‐day‐old Phaseolus vulgaris (cv Nerina) in droplet sizes of 1–10 µl and carrier volumes of 10 to 200 µl per leaf. Decreasing droplet size or increasing carrier volume decreased daminozide penetration, but increased translocation. Plotting the logarithm of the leaf surface/droplet interface area vs daminozide uptake yielded a negative linear relationship, but for translocation an optimum quadratic type relationship was obtained. Some phytotoxicity occurred at low carrier volumes and large droplet sizes. The degree of phytotoxicity was positively related to the amount of daminozide deposited per unit wetted area above 0.7 µg daminozide mm⁻². Below this threshold, there was no visual evidence of phytotoxicity. At the breakpoint, the deposit covered an area of 276 mm² on both primary bean leaf surfaces. Since the maximum in the relationship of translocation with interface area was in close agreement with the threshold amount of deposit above which phytotoxicity occurred, the inverse relationship between daminozide uptake and translocation at low interface areas was attributed to phytotoxicity. © 2000 Society of Chemical Industry     

Uptake, translocation, metabolism and selectivity of glyphosate in Canada thistle and leafy spurge

The uptake, translocation and metabolism of glyphosate [N-(phosphonomethyl) glycine] by Canada thistle (Cirsium arvense (L.) Scop.) (susceptible) and leafy spurge (Euphorbia esula (L.)) (resistant) were examined in an attempt to elucidate the nature of the differential sensitivity. The pattern of uptake and translocation was similar in both species. Glyphosate moved readily in the apoplast and the symplast. High humidity and/or surfactant greatly increased the amount of ¹⁴C-glyphosate absorbed and translocated over that in low humidity and/or without surfactant. No ¹⁴Cmetabolites were detected in either species 1 week after treatment with ¹⁴C-glyphosate. More of a glyphosate spray solution containing a fluorescent dye was received and retained on Canada thistle by virtue of its growth habit than on leafy spurge. More glyphosate should therefore be available for uptake by Canada thistle and this may account for the differential sensitivity of these two species.     

乙烯利对草甘膦在空心莲子草中传导及生物活性的影响

在人工气候室培养空心莲子草,植株经草甘膦与乙烯利混合处理后,测定对植株的抑制作用和草甘膦的吸收与传导量.结果表明,加入乙烯利(100 mg*L-1)后草甘膦(300mg*L-1)对地下根茎抑制率比对照提高了13.6个百分点.植株经乙烯利喷雾处理后,基芽、地下茎和根系中14C-草甘膦含量分别是对照的3.56、1.75和2.35倍.放射性成像图显示,植株地下茎与根系中14C-草甘膦传导量明显高于对照.     

Uptake, translocation and metabolism of the herbicide florasulam in wheat and broadleaf weeds

Florasulam is a triazolopyrimidine sulfonanilide post-emergence broadleaf herbicide for use in wheat (Triticum aestivum L.). The selectivity of florasulam to wheat has been determined to be related primarily to a differential rate of metabolism between wheat with a half-life of 2.4 h and broadleaf weeds with half-lives ranging from 19 to >48 h. To a lesser extent, selectivity, at least for the broadleaf weed cleavers (Galium aparine L.), involves uptake differences. Rate of metabolism data were generated using greenhouse-grown plants injected with radiolabelled florasulam and subsequent extraction and processing by high-performance liquid chromatography (HPLC). Structures of metabolites were determined by isolation for nuclear magnetic resonance and liquid chromatography/mass spectrometry. Wheat plants metabolised florasulam by hydroxylation of the aniline ring para to the nitrogen, followed by conjugation to glucose. Metabolism by broadleaf weeds was so slow that isolation of metabolite was not possible, but comparison of HPLC data suggested hydroxylation as the major pathway.     

Uptake, translocation and metabolism of aminocyclopyrachlor in prickly lettuce, rush skeletonweed and yellow starthistle

BACKGROUND: Aminocyclopyrachlor is a new herbicide proposed to control broadleaf weeds and shrubs in non‐crop and rangeland systems. To gain a better understanding of observed field efficacy, the uptake and translocation of foliar‐applied aminocyclopyrachlor (DPX‐MAT28) and aminocyclopyrachlor methyl ester (DPX‐KJM44) were evaluated in two annuals, prickly lettuce (Lactuca serriola L.) and yellow starthistle (Centaurea solstitialis L.), and one perennial, rush skeletonweed (Chondrilla juncea L.). RESULTS: Absorption and translocation varied between species. While absorption of DPX‐KJM44 was greater than absorption of DPX‐MAT28, rush skeletonweed absorbed the most, followed by yellow starthistle and prickly lettuce. Overall, the total translocation of either herbicide was highest in yellow starthistle, followed by rush skeletonweed and prickly lettuce. Proportional herbicide movement between species was similar, with the majority translocating to developing shoots. However, in rush skeletonweed, early translocation was directed to root tissue. In rush skeletonweed, no DPX‐MAT28 metabolism occurred, while DPX‐KJM44 was rapidly de‐esterified and translocated as DPX‐MAT28. CONCLUSION: Aminocyclopyrachlor absorption and translocation are dependent on active ingredient structure and species sensitivity. Highly sensitive species such as prickly lettuce absorb and translocate less material than relatively less sensitive species such as rush skeletonweed. De‐esterification of DPX‐KJM44 appears to delay translocation of the resulting acid in yellow starthistle and rush skeletonweed. Copyright © 2011 Society of Chemical Industry     

Uptake and translocation of bleaching herbicidal compounds in radish seedlings

The relationship between the hydrophobicity of certain herbicidal compounds and the bleaching pattern caused on radish cotyledons was investigated. Seed treatment with diphenylpyridones, as well as with established herbicides, produced three types of bleaching pattern according to their hydrophobicity. The less hydrophobic compounds caused complete bleaching of both cotyledons, but the compounds with more hydrophobicity caused only partial bleaching. The critical points for whole or partial bleaching were in the range of log K_ow 4–5 (K_ow: octanol/water partition coefficient), and these values were changed slightly with their chemical classes. Uptake of compounds into the seed coat took place rapidly; these compounds were then translocated slowly from the seed coat to the embryo, namely, radicle, abaxial surface of one cotyledon and marginal areas of both cotyledons. Application of these compounds to roots resulted in initial translocation to marginal areas of both cotyledons, with subsequent translocation to the middle area. It is believed that compounds taken up into the radicle were translocated to both cotyledons in a manner similar to that following application to roots. These effects following uptake by seeds can be used as a translaminal and lateral transport assay for bleaching herbicidal compounds in cotyledons.     

氟唑磺隆在野燕麦中的内吸传导特性

新型除草剂氟唑磺隆是磺酰脲类小麦田除草剂,为明确其在野燕麦植株中的内吸传导特性以及为合理使用氟唑磺隆防除杂草策略的制定提供科学依据,分别采用水培法和涂药法研究了氟唑磺隆在野燕麦Avena fatua植株中的传导特性。结果显示:采用水培法以50 mg/L的氟唑磺隆处理野燕麦根部,药后24 h野燕麦根、叶鞘和下部成熟叶中氟唑磺隆含量的占比分别为22%、74%和4%,心叶中未检测出;药后48 h野燕麦根、叶鞘、下部成熟叶和心叶中氟唑磺隆含量的占比分别为23%、58%、8%和11%。采用涂药法以50 mg/L氟唑磺隆处理野燕麦成熟叶片,药后24 h野燕麦下部成熟叶和心叶中氟唑磺隆的含量占比分别为57%和43%,根和叶鞘未检测出;药后48 h野燕麦根、叶鞘、下部成熟叶和心叶中氟唑磺隆的含量占比分别为1%、1%、68%和30%。结果表明,氟唑磺隆能被野燕麦的根吸收,具有优异的自下而上的内吸传导特性;同时氟唑磺隆能被野燕麦的叶片吸收,并可在叶间传导和向根传导。表明氟唑磺隆在野燕麦中具有双向传导的能力。