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1.
Alloxydim-sodium, methyl 3-[1-(allyloxyimino)butyl]-4-hydroxy-6,6-dimethyl-2-oxocyclohex-3-enecarboxylate sodium salt, is a selective herbicide which controls grass weeds in a wide range of broad-leaf crops. Spray retention, tested at two growth stages, was generally greater for the broad-leaf crops (cotton, sugarbeet, flax, beans and peas) than for wild oat (Avena fatua L.), blackgrass (Alopecurus myosuroides Huds), barley and couch grass [Agropyron repens (L.) Beauv.], and did not contribute to selectivity between susceptible and tolerant species. Broad-leaf crops tolerated 2820 g alloxydim-sodium ha?1, three times the recommended rate used to control annual grasses. Differential uptake and translocation were not factors contributing to selectivity. In wild oat, blackgrass and sugarbeet, uptake and translocation of 14C continued during a period of 14 days after treatment with [14C]alloxydim-sodium. Translocation in susceptible and tolerant species was predominately symplastic. Over 40% of the applied 14C was eliminated from treated wild oat, blackgrass and sugarbeet plants within 7 days, due to degradation and volatilisation. A greater proportion of the methanol-soluble radioactivity extracted from leaves and roots was present as water-soluble polar metabolites in sugarbeet, than in wild oats, 7 days after treatment. The proportion of unaltered alloxydim in the organo-soluble fraction of a methanol extract was greater in wild oat than in sugarbeet. Differential metabolism appears to be one of the factors contributing to alloxydim-sodium selectivity between sugarbeet and wild oat.  相似文献   

2.
Wild oat (Avena fatua L.) plants sprayed at the 2-or 3-leaf stages of growth with diclotop-methyl developed chlorosis over the entire leaf blade of all leaves. The leaves became necfrotic 7days after spraying Shool growth was inhibited. In wheat (Triticum aesicum L cv.Waldron) discrete chlorotic areas developed only where the herbicide convicted the 2nd or 3rd leaf with no visible injury so new growth uf'ter treutment. Growth inhibition of susceptible oat (Avena sativa L. cv. Garry) was sensitive to placement of diclutop-methyl near the upica and meristematic sites of the plant. Chlorosis and necrosis were independent of herbicide placement. Selective herbicide placement induced chlorosis only or both chlorosis and growth inhibition Root growth in wild oat and barley (Hordeum rulgare L. cv. Dickson) was strongly inhibited by 1–0 μM diclofop-methyl. Wild oat shoots were killed when seedlings were root-treated with 10 μM diclofop-melhyl. The 100 μM rool treatment killed barley shoots but only stunted the growth of wheat shoots by approximately 50%. In root-ireated wheat plants the shoots were turgid and developed a light purple colour, whereas in foliar-treated plants the shoots developed discrete chlorotic areas.  相似文献   

3.
Over a concentration range of 5.0 × 10?6?7.5 × 10?4M, the selective herbicide difenzoquat (1,2-dimethyl-3,5-diphenyl-1H-pyrazolium) caused more pronounced inhibition of potassium ion (K+) absorption by excised seedling roots of susceptible wild oat (Avena fatua L.) compared to those of tolerant barley (Hordeum vulgare L. cv. Bonanza) or wheat (Triticum aestivum L. cv. Neepawa). At 2.5 × 10?5M difenzoquat, the relative inhibition of K+ (86Rb) absorption by wild oat root segments inceased from 30% with a 10-min uptake period to 75% with an uptake period of 90 min, whereas no inhibition at all was evident for wheat root segments even after a 90-min exposure to the herbicide. An ion efflux compartmental analysis procedure demonstrated that difenzoquat did not affect the passive permeability properties of the plasma membrane of wild oat root cells. The experimental findings indicated that difenzoquat interfered directly with the process of active ion transport across the plasma membrane of root cells.  相似文献   

4.
In order to clarify the action mechanism of fluazifop-butyl, an aryloxyphenoxypropionate (AOPP) herbicide in bristly starbur (Acanthospermum hispidum DC.), a unique fluazifop-butyl-susceptible broad-leaved weed, ethylene evolution and membrane lipid peroxidation in the plant seedlings were investigated. Foliar application of fluazifop-P-butyl induced ethylene evolution only from bristly starbur, but not from oat (Avena sativa L.), another fluazifop-butyl-susceptible species, and two tolerant species, pea (Pisum sativum L.) and hairy beggarticks (Bidens pilosa L.). The other AOPP herbicides, quizalofop-ethyl and fenoxaprop-ethyl, and a cyclohexanedione (CHD) herbicide, sethoxydim, did not enhance ethylene production from bristly starbur. This fluazifop-butyl-induced ethylene production in bristly starbur was completely suppressed by aminoethoxyvinylglycine (AVG), a 1-aminocyclopropane-1-carboxylic acid (ACC) synthase inhibitor, but not by p-chlorophenoxyisobutyric acid (PCIB), an anti-auxin compound, suggesting this evolved ethylene was not auxin-induced. Phytotoxic action by fluazifop-P-butyl (5 μM) in bristly starbur was reduced markedly by two lipid-soluble antioxidants, vitamin E, and ethoxyquin. The ethylene production from the plant was also inhibited by these two antioxidants. Content of malondialdehyde, an indicator of lipid peroxidation, increased only by fluazifop-P-butyl in bristly starbur seedlings but not in oat, and this increase was inhibited by ethoxyquin. These results strongly suggest that the primary site of action for fluazifop-butyl in bristly starbur is on the membranes and active oxygen species and/or free radicals are involved in peroxidation. Ethylene evolution is probably induced by these reactive oxygen species.  相似文献   

5.
An expérimental procedure was designed to provide a simple model for types of analyses necessary to determine weed density thresholds for advantageous use of crop plants engineered for herbicide resistance. Oilseed rape (Brassica napus L., cv. Tower) biotypes resistant (RES) and susceptible (SUS) to atrazine were used as model crop plants, and wild oat (Avena fatua L.) was used as the model weed. Along a wild oat density gradient equivalent to 0–128 plants m?2, RES plants consistently experienced biomass and yield reductions of approximately 10–20% compared to SUS plants. When atrazine was applied at 1.5 kg ha?1 to control wild oats competing with RES plants, RES biomasses and yields were stabilized at the same level as that where 25–30 wild oats m?2 reduce yields of SUS plants. This implies that with wild oat densities of 25–30 plants m?2, it becomes agronomically advantageous to crop with RES plants plus atrazine rather than to crop with higher-yielding SUS plants.  相似文献   

6.
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.  相似文献   

7.
The effects of infection by the powdery mildew fungusErysiphe graminisf.spavenaewere studied in one line of wild oat (Avena fatua), and two cultivars, Lustre and Peniarth, of cultivated oat (A. sativa) to determine if the wild oat was more tolerant of infection than the two cultivated oats. Seven weeks after inoculation, when the plants were 10-weeks-old with fully expanded flag leaves, the fungus had colonized approx. 40% of the leaf surfaces of wild oat and cv. Lustre but only about 30% of the leaf surfaces of cv. Peniarth. The lower leaves of cv. Peniarth were at least as susceptible, if not more so, than those of the other two lines but the upper leaves, including the flag leaf, were much more resistant. Although cv. Peniarth supported the production of about half the number of mildew conidia as the wild oat and cv. Lustre its total dry weight and grain yield were reduced to the greatest extent. The wild oat was clearly much more tolerant of mildew infection than cv. Peniarth and slightly more tolerant than cv. Lustre. The greater tolerances of the wild oat and cv. Lustre compared to cv. Peniarth appeared to be due to the lower sensitivities of their metabolism to the activities of the mildew fungus.  相似文献   

8.
Residues from mature, harvested crops of sorghum (Sorghum bicolor Moench.), sunflower (Helianthus annuus L.), oilseed rape (Brassica napus L.), wheat (Triticum aestivum L.) and field pea (Pisum sativum L.), exhibited selective effects on weed germination and growth under field conditions. Weed species in the study included Avena fatua L., Avena sterilis ssp. ludoviciana (Durieu) Nyman, Echinochloa crus-galli (L.) Beauv., Phalaris aquatica L., Phalaris paradoxa L., Lolium perenne L., Vulpia myuros (L.) Gmel., Hibiscus trionum L., Polygonum aviculare L., Bilderdykia convolvulus (L.) Dumort. and Lamium amplexicaule L. All crop residues tested, and in particular wheat and pea residues, promoted the germination and growth of A. fatua and A sterilis ssp. ludoviciana. Other grass weeds, however, were inhibited by the presence of crop residue, the extent of inhibition being dependent on residue type. Germination response of dicotyledonous weed species was also a function of residue type, H. trionum numbers were significantly higher in plots where oilseed rape, sorghum or sunflower residue had been incorporated, while L. amplexicaule was inhibited by these residue types and stimulated by pea and wheat residues.  相似文献   

9.
Differential sensitivity of wild oat (Avena fatua L.) and wheat (Triticum aestivum L.) to barban (4-chloro-2-butynyl-m-chlorocarbanilate) was highest when barban was applied to the coleoptile. The coleoptile acts as a physical and physiological barrier to reduce the concentration of free barban in the stem section where the sensitive meristematic sites are located. Metabolism of barban was higher ïn the coleoptile of tolerant wheat than in that of susceptible wild oat. Free barban concentration was higher in the stem of wild oat than in the stem of wheat after 24 hr, but after 48 hr, concentrations were similar. The coleoptile appears to enhance the differential sensitivity to barban between wild oat and wheat.  相似文献   

10.
The herbicide diclofop-methyl caused an early and pronounced inhibition of the incorporation of [14C]acetate into leaf lipids of the sensitive plant species maize (Zea may L.), wild oat (Avena fatua L.), and barnyardgrass (Echinochloa crus-galli L.). With an EC50 value of approximately 10?7M inhibition was already apparent 0.5–4 hr after herbicide application. The fatty acid biosynthesis of tolerant bean (Phaseolus vulgaris L.), sugar beet (Beta vulgaris L.), and soybean (Glycine max L.) was not affected, with one exception [wheat (Triticum aestivum L.) belongs to the more tolerant species]; the inhibition of fatty acid biosynthesis, however, was in the same order of magnitude as in sensitive plants. More detailed studies showed that in wheat a recovery from inhibition of fatty acid biosynthesis occurred. Four days after herbicide application (0.18 kg diclofop-methyl/ha) in wheat normal fatty acid biosynthesis was restored, whereas in sensitive maize a 60% inhibition was maintained over the whole experimental period (8 days). The results support the view that tolerance of wheat to diclofop-methyl is based on its inactivation in leaves, whereas the tolerance of dicotyledonous species may probably lie at the level of the site of action of diclofop-methyl. In experiments with intact leaves, the inhibition of fatty acid biosynthesis resulted in an enhanced flow of [14C]acetate into organic acids and amino acids. This effect, however, was not always reproducible in experiments with leaf pieces or isolated root tips.  相似文献   

11.
A national survey was conducted in Finland from 1982 to 1984 to determine the main weed species in spring cereals and the efficacy of herbicides on Finnish farms. The most common dicotyledonous weeds producing the highest biomass in spring cereals were Chenopodium album L., Galeopsis spp. L., Stellaria media (L.) Vill. and Lapsana communis L. The main grass weed was Elymus repens (L.) Gould. The average reduction of weed biomass by herbicide treatment was 75%. More reliable efficacy was obtained with herbicide mixtures than with MCPA alone.  相似文献   

12.
Vulpia bromoides is a grass species naturally tolerant to acetolactate synthase (ALS) and acetyl-coenzyme A carboxylase (ACCase) inhibiting herbicides. The mechanism of tolerance to ALS herbicides was determined as cytochrome P450-monooxygenase mediated metabolic detoxification. The ALS enzyme extract partially purified from V. bromoides shoot tissue was found to be as sensitive as that of herbicide susceptible Lolium rigidum to ALS-inhibiting sulfonylurea (SU), triazolopyrimidine (TP), and imidazolinone (IM) herbicides. Furthermore, phytotoxicity of the wheat-selective SU herbicide chlorsulfuron was significantly enhanced in vivo in the presence of the known P450 inhibitor malathion. In contract, the biochemical basis of tolerance to ACCase inhibiting herbicides was established as an insensitive ACCase. In vitro ACCase inhibition assays showed that, compared to a herbicide susceptible L. rigidum, the V. bromoides ACCase was moderately (4.5- to 9.5-fold) insensitive to the aryloxyphenoxypropionate (APP) herbicides diclofop, fluazifop, and haloxyfop and highly insensitive (20- to >71-fold) to the cyclohexanedione (CHD) herbicides sethoxydim and tralkoxydim. No differential absorption or de-esterification of fluazifop-P-butyl was observed between the two species at 48 h after herbicide application, and furthermore V. bromoides did not detoxify fluazifop acid as rapidly as susceptible L. rigidum. It is concluded that two co-existing resistance mechanisms, i.e., an enhanced metabolism of ALS herbicides and an insensitive target ACCase, endow natural tolerance to ALS and ACCase inhibiting herbicides in V. bromoides.  相似文献   

13.
Abstract

Whole-plant response experiments in pots and field experiments over two years were conducted to study the resistance levels and chemical control options of sterile oat (Avena sterilis L.) in typical wheat production areas of northern Greece. Data revealed high levels of resistance to the ACCase-inhibiting herbicides clodinafop-propargyl and fenoxaprop-p-ethyl in all sterile oat populations, noticeable levels of resistance of some populations to tralkoxydim and pinoxaden, and high susceptibility of four out of the five populations to the prepackage mixture [mesosulfuron?+?iodosulfuron]. The addition of chlorpyrifos did not improve the efficacy of all herbicides against the resistant populations, implying target-site resistance in the populations tested rather than resistance due to P450-mediated enhanced herbicide metabolism. These results indicated that all populations were at least four times more resistant to clodinafop-propargyl, fenoxaprop-p-ethyl and diclofop-methyl than the susceptible populations, but noticeable levels of resistance of some sterile oat populations to tralkoxydim, pinoxaden and the prepackage mixture [mesosulfuron?+?iodosulfuron] were also recorded. However, viable options for chemical control of this weed still exist.  相似文献   

14.
Ambrosia artemisüfolia L. (common ragweed) and Digitaria ischaemum Schreb. (smooth crabgrass) are not controlled by nicosulfuron and rimsulfuron at the highest recommended application rates, whereas Panicum miliaceum L. (wild proso millet), Amaranthus retroflexus L. (redroot pigweed) and Avena fatua L. (wild oat) are susceptible. The foliar absorption and translocation of 14C-nicosulfuron and 14C-rimsulf uron were studied in these weed species up to 48 h after treatment (HAT). Differences in herbicide uptake and translocation were not correlated with the species susceptibility. By 48 HAT, more than 50% of both herbicides remained on the treated leaf surface. Foliar absorption of rimsulfuron was greater than that of nicosulfuron in A. retroflexus, P. miliaceum and A. artemisüfolia. Most of the absorbed herbicide remained in the treated leaf of each weed species. Export of 14C–nicosulfuron ranged from 28 to 54% of that absorbed, in contrast to 15 to 39% for 14C–rimsulfuron. The absorption and translocation rates of both herbicides were highest within the initial 6 HAT, and decreased thereafter. Both herbicides showed approximately the same distribution pattern within each weed species.  相似文献   

15.
Influence of 2,4-D on toxicity of diclofop-methyl to Avena sativa (cv. Selma) and Arena fatua at 2·5 leaf stage has been evaluated under controlled conditions. Effects of 2,4-D on the fate of diclofop-methyl in cultivated oat have also been studied. Mixture with 2,4-D reduced the toxicity of diclofop-methyl to both species. When applied immediately after diclofop-methyl treatment, 2,4-D still reduced herbicide toxicity to wild oat. This reduction was smaller in cultivated oat. and was only observed at higher phytotoxicity. No interaction was observed when a 10-day period separated the two applications. In mixture, 2,4-D enhanced diclofop-methyl penetration and diclofop acid conjugation in cultivated oat, and it slightly increased conjugation when applied separately. None of these effects clearly explain the reduction of diclofop-methyl toxicity by 2, 4-D in cultivated oat. Other processes are possibly involved and could be connected with the site of action of diclofop-methyl.  相似文献   

16.
Competition between wild oat (Avena fatua L.) and wheat (Triticum aestivum L.) was studied in two experiments; a replacement series model and a technique for separation of root and shoot systems. Wild oat and wheat in association resulted in a relative yield total very close to unity showing that the two species were‘crowding for the same space’(or competing for the same resources) and were‘mutually exclusive'. Wild oat was more competitive than wheat, as shown by its aggressivity relative to wheat, relative yields, shoot dry weights and other plant attributes. The greater competitive ability of wild oat was predominantly due to its greater root competitive ability, while the two species had similar shoot competitive ability. Root competition had a much greater effect on the relative performance of the two species than did shoot competition. The effects of root and shoot competition were additive.  相似文献   

17.
The feasibility of achieving selective wild oat (Avena fatua L.) control in a stand of the Australian oat (Avena sativa L.) cv. Savena I was examined. Diclofop-methyl was applied at rates of 0·4–0·7 kg a.i. ha?1 at the three- and five-leaf stages of A. fatua (84–132 culms m2). Although all rates of diclofop-methyl caused initial chlorosis and necrosis to the crop, the subsequent control of A. fatua permitted increased crop tillering. Avena fatua control and crop yield response were maximized when diclofop-methyl was applied at the three-leaf stage. Crop grain yield was increased by as much as 32% and 22% during 1984 and 1985, respectively. In the absence of A. fatua competition, crop shoot dry weight at ear emergence was reduced only where diclofop-methyl was applied at 0·6 or 0·7 kg ha?1. However, final grain yield was not reduced by any treatment. Only 11 of 240 cultivars or lines tolerated diclofop-methyl, and none reached the level attained by Savena I and a closely related Australian line [(Irwin × (West × New Zealand Cape/42)) × West]/24. The nature of the inheritance of diclofop-methyl tolerance was examined (1983–1985) by crossing and backcrossing (BC) Savena I with four diclofop-methyl susceptible, but agronomically superior, lines. Inheritance of diclofop-methyl tolerance appeared to be controlled by two genes, with susceptibility being dominant to tolerance in F3, BCIF2 and BCIF3 lines.  相似文献   

18.
The mechanisms of AOPP herbicide resistance in twoAlopecurus myosuroidesbiotypes were investigated. Resistant biotype Peldon A1, which is highly resistant to the phenyl-urea chlorotoluron, is moderately resistant to the AOPP herbicides diclofop-methyl, fenoxaprop-ethyl, fluazifop-P-butyl, and the CHD tralkoxydim. Resistant biotype Lincs. E1, which is only moderately resistant to chlorotoluron, is highly resistant to the AOPP herbicide fenoxaprop-ethyl, and moderately resistant to diclofop-methyl, fluazifop-P-butyl, and the CHD tralkoxydim. There is no clear evidence of resistance to the CHD sethoxydim in either biotype. Both Peldon A1 and Lincs. E1 exhibited moderately enhanced metabolism of diclofop-methyl. The approximate half life of diclofop was 8 and 9 HAT, respectively, compared to 17 HAT for the susceptible Rothamsted biotype. Peldon A1 showed moderately enhanced metabolism of fenoxaprop-P-ethyl. However, in the highly resistant Lincs. E1, fenoxaprop-P-ethyl metabolism rates were intermediate between Peldon A1 and the susceptible biotype. Fenoxaprop-P-ethyl metabolism inA. myosuroideswas not significantly reduced by inhibitors of cytochrome P450: PBO, tetcyclasis, or ABT. While enhanced herbicide metabolism can account for the moderate AOPP/CHD resistance observed in Peldon A1in vivo, it cannot account in total for fenoxaprop-ethyl resistance in Lincs. E1. Lincs. E1 may possess one or more additional resistance mechanism.  相似文献   

19.
Barnyardgrass (Echinochloa crus-galli (L.) Beauv.), an annual species of the family Poaceae, is a major weed problem in rice-producing countries throughout the globe. Synthetic herbicides can effectively control this grass in rice paddies, but the development of resistant biotypes after the continuous use of the same active ingredients has led to low herbicide efficacy and yield losses. In this review, a summary of resistant-barnyardgrass cases in global rice production is reported based on data from the International Herbicide-Resistant Weed Database. The first case of resistant barnyardgrass in rice paddies was to the photosystem-II inhibitor propanil in the late 1980s. Eighty-five (85) out of 116 cases in the period from 1986 to 2022 refer to resistant barnyardgrass (E. crus-galli var. crus-galli, E. crus-galli var. formosensis and E. crus-galli var. zelayensis) in 16 countries. Barnyardgrass has been found resistant to acetolactate synthase (ALS) inhibitors (34 cases), acetyl-CoA carboxylase (ACCase) inhibitors (23 cases), photosystem-II inhibitors (11 cases), auxin mimics/cellulose biosynthesis inhibitors (9 cases), very long chain fatty acid inhibitors (6 cases), and microtubule assembly inhibitors (1 case). The majority of all resistance cases reported to the active ingredients penoxsulam, bispyribac-sodium, and imazamox (ALS inhibitors), cyhalofop-butyl and fenoxaprop-ethyl (ACCase inhibitors), propanil (photosystem-II inhibitors), and quinclorac (auxin mimics/cellulose biosynthesis inhibitors). Although target-site resistance with specific mutations has been identified, non-target site resistance mainly through herbicide detoxification is also of great concern increasing the chance of multiple herbicide resistance evolution. Rotation of herbicides should be adopted concerning the modes of action used as well as the application methods to mitigate resistance evolution of this weed in rice paddies.  相似文献   

20.
The survey was carried out over an area representing about 47% of the cereal acreage of the United Kingdom. Estimates of the acreage of fields containing wild oat (Avena fatua L. and A. ludoviciana Dur) ranged from 15% (Northern Ireland) to 74% (England, South West Region). The degree of infestation over the total acreage was 58%‘light’, 34%‘medium’, and 8%‘heavy’. Blackgrass (Alopecurus myosurodies Huds.) was found only in the central and southern regions, estimates of the infested cereal field acreage ranging from 2% (Wales) to 23% (South East England). Nine per cent of the fields were rogued for wild oat. On average, only 10% of the infested acreage received herbicide treatment for wild oat and blackgrass though, in some regions, up to 23 % was treated. The timing of treatment and the herbicide used were recorded. Information on the extent and type of herbicide used for broad-leaved weeds was also recorded. Data on sowing dates of the crops, the previous cropping, previous infestations, the soil type and the state of field drainage were obtained and were correlated with the incidence of wild oat and blackgrass where relevant.  相似文献   

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