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1.
P. B. MARRIAGE 《Weed Research》1975,15(5):291-298
Atrazine, simazine, diuron, and linuron applied to soil increased the percentage moisture of oat (Avena sativa L.) shoots in bioassays at the lowest dose tested of 0·25 ppm. Further increases occurred up to 2 ppm but at higher concentrations the percentage moisture decreased. At all doses of each herbicide, shoot dry weight was decreased. In oats grown on soil collected from a peach orchard which had received repeated annual applications of these herbicides, the percentage moisture of the oat shoots was higher than the control value whenever the oat dry weight was decreased and provided a method of residue detection as sensitive as dry weight measurements. Treatment of oats by soil application of the above herbicides in bioassays also caused increases in the electrical conductivity of an aqueous extract of the oat shoots per mg of dry weight and this characteristic was slightly more sensitive than dry weight in detecting herbicides in orchard soil. The conductivity of the extract per mg of water in the shoots, however, only increased as percentage moisture decreased. The weight of neutral water-soluble material in oat shoots decreased much more rapidly than dry weight in bioassays with standard herbicide concentrations. Determination of the weight of neutral water-soluble material in oat plants grown on orchard soil samples indicated the presence of herbicide residues in 50% of the cases in which residues were not detectable by dry weight. The weight of neutral material as a percentage of dry weight was almost as sensitive. Chemical analysis of soil in which oat plants had a decreased level of neutral water-soluble compounds indicated that this characteristic had a lower limit of detection for herbicide residues of approximately 0.10 ppm. 相似文献
2.
W. PESTEMER 《Weed Research》1976,16(6):357-363
A quantitative bioassay for estimation of photosynthetic inhibitors in soils A bioassay procedure for the quantitative determination of photosynthetic inhibitors in soil samples, hydroponic and staple fibres is described In detail. Garden cress (Lepidium sativum L.) has proved very suitable as test plant. Monolinuron and methabenzthiazuron were used to demonstrate the capability of the method for estimating herbicidal activity and plant availability, and for monitoring the total residues of herbicides in different soils. The method was found capable of assaying quantitatively concentrations as low as 0,04 ppm monolinuron. Photosynthetic inhibitors did not affect germination or seedling growth during the first 5 days after sowing: retardation of growth occurred only after food reserves in the endosperm were consumed. Therefore the content of food reserves in the cress seeds was determined in a dark-germination test and substracted from all yield results to give the dry matter yield under herbicide stress. 相似文献
3.
K. HURLE 《Weed Research》1977,17(1):25-32
A comparison of bioassays with chemical methods of analysis for the determination of atrazine, 2,4-D, DNOC and napropamide in the soil The degradation of atrazine (2-chloro-4-ethylamino-6-isopropylamino-s-triazine), 2,4-D (2,4-dichlorophenoxyacetic acid), DNOC (4,6-dinitro-o-cresol) and napropamide (2-(α-naphthoxy)-NN-diethylpropionamide) in the soil was investigated using chemical methods of analysis and bioassays and the results were compared. For the biological determination, millet (a sorghum/Sudan grass hybrid) was used for atrazine in a glasshouse test, a cress (Lepidium sativum L.) root test for 2,4-D and DNOC. and an oat (Avena sativa L.) root test for napropamide. The instrumental determinations were carried out using gas chromatography for atrazine, 2,4-D and napropamide, and colorimetry for DNOC. The bioassays showed degradation kinetics typical for the herbicides but quantitative determination was unsatisfactory. Compared with the instrumental methods, bioassays indicated more rapid degradation in the case of atrazine and napropamide and lower initial concentrations in the case of 2,4-D and DNOC. Possible causes for these differences are discussed and from the results it is inferred that quantitative determinations with bioassays are only justifiable where their accuracy has been verified with established chemical methods. 相似文献
4.
Repeated use of ACCase‐ and ALS‐inhibiting herbicides in northern Greece has resulted in the evolution of a population of Lolium rigidum resistant to diclofop and chlorsulfuron. The biotype from Athos was highly resistant to diclofop and also exhibited differential cross‐resistance to clodinafop, fluazifop, tralkoxydim and sethoxydim. Assay of ACCase activity confirmed that the resistant biotype was tenfold more resistant to diclofop than the susceptible biotype, suggesting that the resistance mechanism could involve an altered target site. The diclofop‐resistant biotype has also exhibited multiple resistance to chlorsulfuron and the mechanism for this is unknown. Seed‐bioassay was found to be a rapid, cheap and reliable method to identify populations of L rigidum resistant to ACCase inhibitors and chlorsulfuron. Moreover, root elongation in the seed bioassay was more sensitive to ACCase inhibitors and chlorsulfuron than shoot elongation. © 2000 Society of Chemical Industry 相似文献
5.
Status of black grass (Alopecurus myosuroides) resistance to acetyl-coenzyme A carboxylase inhibitors in France 总被引：1，自引：0，他引：1
C DÉLYE Y MENCHARI J-P GUILLEMIN† A MATÉJICEK S MICHEL C CAMILLERI‡ & B CHAUVEL 《Weed Research》2007,47(2):95-105
We assessed the contributions of target site‐ and non‐target site‐based resistance to herbicides inhibiting acetyl‐coenzyme A carboxylase (ACC) in Alopecurus myosuroides (black grass). A total of 243 A. myosuroides populations collected across France were analysed using herbicide sensitivity bioassay (24 300 seedlings analysed) and ACC genotyping (13 188 seedlings analysed). Seedlings resistant to at least one ACC‐inhibiting herbicide were detected in 99.2% of the populations. Mutant, resistant ACC allele(s) were detected in 56.8% of the populations. Among the five resistant ACC alleles known in A. myosuroides, alleles containing an isoleucine‐to‐leucine substitution at codon 1781 were predominant (59.5% of the plants containing resistant ACC alleles). Comparison of the results from herbicide sensitivity bioassays with genotyping indicated that more than 75% of the plants resistant to ACC‐inhibiting herbicides in France would be resistant via increased herbicide metabolism. Analysis of herbicide application records suggested that in 15.9% of the populations studied, metabolism‐based resistance to ACC‐inhibiting herbicides was mostly selected for by herbicides with other modes of action. Our study revealed the importance of non‐target site‐based resistance in A. myosuroides. Using herbicides with alternative modes of action to control populations resistant to ACC‐inhibiting herbicides, the recommended management approach, may thus be jeopardised by the widespread occurrence of metabolism‐based resistance mechanisms conferring broad‐spectrum cross‐resistance. 相似文献
6.
Avena fatua (wild oat) populations with resistance (R) to one or more herbicides have been described in numerous cropping systems worldwide. We previously reported that the R3 and R4 wild oat populations from Montana, USA, were resistant to four herbicides representing three different modes of action: tralkoxydim [acetyl‐CoA carboxylase (ACCase] inhibitor), imazamethabenz and flucarbazone [acetolactate synthase (ALS) inhibitors] and difenzoquat (growth inhibitor). We now quantify resistance levels of these populations to triallate [very long chain fatty acid (VLCFA) biosynthesis inhibitor], pinoxaden (ACCase inhibitor) and paraquat (photosystem I inhibitor). Glasshouse dose–response experiments showed that, compared with the means of two susceptible (S) populations, the R3 and R4 populations were 17.5‐ and 18.1‐fold more resistant to triallate, 3.6‐ and 3.7‐fold more resistant to pinoxaden, respectively, and 3.2‐fold (R3) more resistant to paraquat. Pre‐treatment of R plants with the cytochrome P450 inhibitor malathion partially reversed the resistance phenotype for flucarbazone (both populations), imazamethabenz (R4), difenzoquat (R4) and pinoxaden (R3), but not for tralkoxydim, fenoxaprop‐P‐ethyl or triallate. Target site point mutations known to confer resistance to ALS or ACCase inhibitors were not detected via DNA sequencing and allele‐specific PCR assays in R plants, suggesting the involvement of non‐target site resistance mechanism(s) for these herbicides. Together, our results complete the initial characterisation of wild oat populations that are resistant to seven (R3) or six (R4) herbicides from five or four mode of action families respectively. 相似文献
7.
C. FEDTKE 《Weed Research》1987,27(3):221-228
inhibitory activities of existing graminicides on root regeneration from monocotyledonous (oat) and dicotyledonous (soybean) plant cuttings in the light, in the dark and on algal growth were compared with the respective inhibitory activities of the new herbicide 2-(2-benzothiazo-lyl-oxy)-N-methyl-N-phenylacetamide (mefenacet). The mefenacet activity spectrum resembled that of the α-chloroacetamide herbicides. Herbicide groups of other structure-activity can be distinguished by their distinct activity spectrum. The mono-oxygenase inhibitors piperonyl but-oxide (PBO) and 1-aminobenzotriazole (ABT) were found to antagonize the inhibitory activities of herbicides from the thiolcarbamate, α-chloroacetamide, and oxyacetic acid amide structure groups in the oat rooting and leaf growth tests. The critical evaluation of the presently available information on graminicide and safener mode of action suggests the concept that lipid biosynthesis on the physiological level and mono-oxygenase type enzymes on the biochemical level may hold the target sites for many of the graminicides and safeners discussed. 相似文献
8.
Summary. The root and shoot growth of oat (Avena saliva L.) and squash (Cucurbita maxima Duchesne) was reduced in proportion to propachlor concentration. Corn (Zea mays L.) root growth was inhibited only by concentrations of 16 ppm and higher. Cell division in onion (Allium cepa L.) root tips was reduced by propachlor and totally inhibited by 16 ppm. Auxin-induced cell elongation of oat coleoptiles was inhibited in proportion to propachlor concentration. Propachlor treatment prevented the normal senescence of squash cotyledons by inhibiting the autolysis of proteinaceous and lipid reserves. Effets morphologiques, anatomiques et biochimiques du propachlore sur la croissance des plantules Riisumi. 相似文献
9.
Summary. We conducted studies to determine the effects on corn (Zea mays L, var. Indiana 654) and pea (Pisum sativum L. var. Alaska) of localizing various herbicides in the soil, using a double plastic pot technique which ensured separate exposure of the root and shoot zones of the plants to treated soil. Effects on corn and pea were similar in relation to site of uptake. 2,4-D-amine, naptalam, simazine, diuron and dalapon-sodium entered primarily through the roots. Some shoot entry and also severe inhibition of roots occurred in soil treated with 2,4-D and naptalam; these were noticed only to a slight extent with the other three herbicides. EPTC, chlorpropham and trifluraiin were most effective when applied to the shoot zone. Little effect on foliage growth was evident when the root zone alone was treated. However, roots in treated soil were severely inhibited by these three herbicides. Dinoseb displayed a contact type of action, injuring both shoots and roots. Treatment of both zones had an additive effect. Entry of chlorthal-methyl which was tested on a susceptible species, sorghum (Sorghum vulgare Pers.) was mainly through the shoot, with only a slight effect on top growth when roots alone were treated. Roots in treated soil were slightly inhibited. Localisation de l'absorption des herbicides appliqués sur le sol 相似文献
10.
Competition between vegetative plants of wild oat (Avena fatua L.) and wheat (Triticum aestivum L.) 总被引：1，自引：0，他引：1
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
11.
Woldeyesus Sinebo D.S.H. Drennan 《European journal of plant pathology / European Foundation for Plant Pathology》2001,107(9):849-860
The effects of nitrogen and the extent of sorghum root infection by Striga hermonthica on host-parasite association during vegetative growth were studied using a split root system in a 3 × 3 factorial combination of N (37mg on one, 18.5 or 37mg on both root-halves) and Striga (no, one or both root-half infection). High N increased sorghum shoot weight by 22% more than low N, but did not significantly affect Striga growth 64 days after transplanting sorghum (DAP). Striga reduced sorghum stem height and weight by 22% and 25% at 38 DAP, and by 34% and 36% at 64 DAP, respectively. Leaf weight was not affected. Striga stimulated root growth 38 DAP, but not 64 DAP. In partially infected sorghum, 64 DAP, the parasite shoot number, shoot height and shoot dry weight were 36%, 46% and 35%, respectively and host shoot dry matter was 142% of those in fully infected plants, indicating an inverse relationship between the degree of host root infection and the level of resistance. The results suggest that sorghum released resistance-confering substances to the infection points after sensing infection. When infection points are widely distributed as in fully infected sorghum, less of such substances appear to render the host more vulnerable. 相似文献
12.
Summary. The root and shoot growth of oat (Avena sativa L.) and green foxtail (Setaria viridis (L.) Beauv.) were generally reduced proportionately to the concentration of chlorthal dimethyl applied. Foxtail shoot growth was stimulated by a concentration of 2 ppm. Cells in the shoot and root meristems of treated plants were completely disarranged and considerably hypertrophied. Differentiation was irregular and extended nearer the apices in tissue of treated seedlings than in normal tissue. Histochemical tests showed that the amount of starch, proteins and nucleic acids in seedling tissue decreased with an increase of chlorthal dimethyl concentration, whereas the endosperm of the seeds retained more starch and protein than the controls. The walls of shoot nieristem and root epidermal cells were thickened or altered so as to stain more intensely than corresponding cells in untreated tissue. Effet du diméthyle chlorthal sur l'anatomie des plantules d'avoine et de séaire 相似文献
13.
The influence of time of emergence of wild oat (Avena fatua L.) on its competition with wheat (Triticum aestivum L.) was studied, using boxes that allowed separation of root and shoot competition. The relative yield total for mixtures of wild oat and wheat, grown under different forms of competition and with different wild oat sowing times, was very close to unity, indicating that the two species competed fully for limiting resources. Wild oat was more competitive than wheat when the two species were sown simultaneously, due largely to its greater root competitive ability; the two species had similar shoot competitive abilities. When wild oat was sown 3 or 6 weeks later than wheat, wheat was more competitive than wild oat and the production of wild oat panicles was prevented. This was mainly the result of greater root competitive ability of the wheat, although shoot competitive ability was also greater. The effects of root and shoot competition were additive. It is concluded that in order to prevent the return of wild oat seeds to the soil, and hence obtain long-term benefit, it is necessary to control the wild oat seedlings emerging within the first 3 weeks after drilling a wheat crop. 相似文献
14.
野燕麦对精噁唑禾草灵、炔草酯敏感性差异测定 总被引：3，自引：3，他引：0
为明确不同野燕麦种群对精噁唑禾草灵和炔草酯的敏感性水平,采用整株生物测定与种子生物测定分别检测了河南、湖北、江苏三省共11个野燕麦种群对精噁唑禾草灵和炔草酯的敏感性。结果表明,2种测定方法获得的野燕麦种群对2种除草剂的敏感性基本一致。整株生物测定结果显示,不同野燕麦种群对精噁唑禾草灵和炔草酸的敏感性存在显著差异,其中,金水闸野燕麦种群对精噁唑禾草灵和炔草酯敏感性最高,其GR50值（有效成分）分别为2.46、3.65 g/hm2,而辉县野燕麦种群对精噁唑禾草灵和炔草酯敏感性最低,GR50值（有效成分）分别为15.00、23.12 g/hm2,其余野燕麦种群对精噁唑禾草灵和炔草酯的敏感性介于金水闸种群与辉县种群之间。种子生物测定结果与整株生物测定结果趋势一致,但表现出的敏感性略高。 相似文献
15.
BACKGROUND: The widespread acceptance of reduced‐tillage farming in cereal cropping systems in the Pacific Northwest of the United States has resulted in increased use of herbicides for weed control. However, soil residual concentrations of widely used imidazalone herbicides limit the cultivation of barley, which is more sensitive than wheat. In addition, increased severity of the root rot disease caused by Rhizoctonia solani is associated with reduction in tillage. Many crops exhibit altered disease responses after application of registered herbicides. In this study, the injury symptoms in barley caused by sublethal rates of two acetolactate synthase (ALS)‐inhibiting herbicides, imazamox and propoxycarbazone‐sodium, were assessed in factorial combinations with a range of inoculum concentrations of the root rot pathogen Rhizoctonia solani AG‐8. RESULTS: Both herbicides and pathogen had negative impacts on plant growth parameters such as root and shoot dry weight, shoot height and first leaf length, and interactions between pathogen and herbicide were detected. CONCLUSIONS: The results suggested that sublethal rates of herbicides and R. solani could alter severity of injury symptoms, possibly owing to the herbicide predisposing the plant to the pathogen. Copyright © 2012 Society of Chemical Industry 相似文献
16.
Weeds resistant (R) to herbicides are widespread worldwide. Bidens subalternans is one of the most troublesome weeds in conventional soyabean fields in Brazil, and in a crop rotation system of cotton/soyabean and maize/soyabean some populations had evolved resistance to acetolactate synthase (ALS)-inhibiting herbicides. Bidens subalternans plants suspected of resistance were observed in soyabean fields where the main ALS-inhibiting herbicide sprayed is chlorimuron-ethyl. To confirm and characterise the resistance of B. subalternans to ALS inhibitors, whole-plant bioassays were conducted in 2006 and 2008. ALS in vivo enzyme bioassays were also conducted in 2007. In both bioassays, the R biotype showed cross-resistance to four chemical families of ALS-inhibiting herbicides. According to whole-plant level tests the R biotype showed 498-, 797-, 726- and >877-fold resistance to chlorimuron-ethyl, imazethapyr, cloransulam-methyl and pyrithiobac-sodium herbicides respectively. The R biotype was also 17-, 166-, 436- and 516-fold R to chlorimuron-ethyl, imazethapyr, cloransulam-methyl and pyrithiobac-sodium herbicides, respectively, based on the enzyme assay. Therefore, the herbicide-R B. subalternans can no longer be controlled by any ALS-inhibitor herbicides. Integrated control methods involving alternative herbicide with different modes of action are needed, to avoid yield losses in conventional soyabean fields in Brazil that are infested by ALS-R B. subalternans populations. 相似文献
17.
Herbicide bioassay 总被引：4，自引：0，他引：4
J. C. STREIBIG 《Weed Research》1988,28(6):479-484
One of the most commonly used techniques to assess the efficacy of herbicides is to apply to the principle of bioassays. A bioassay is defined as an experiment for estimating the potency of a herbicide by analysis of the reaction that follows its application to living organisms. The analysis of variance is central to most applications of statistical methods in the analysis of experiments. This is true for bioassay, but perhaps the fundamental importance of regression and related concepts is here particularly apparent. The purpose of this presentation is to quantify herbicidal effects of applying non-linear regression models to herbicide bioassays, and to demonstrate how some general hypotheses about the mode of action of the assayed herbicides can be incorporated into the regression models. The validity of herbicide bioassay data is discussed in view of the general principles used in bioassay in other biological sciences. 相似文献
18.
Hamidreza Sasanfar Eskandar Zand Mohammad A. Baghestani Mohammad J. Mirhadi Mohsen B. Mesgaran 《Phytoparasitica》2017,45(3):419-428
The level of resistance and patterns of cross-resistance to clodinafop, sethoxydim, and pinoxaden were examined in 12 putative resistant and one susceptible populations of winter wild oat (Avena ludoviciana) collected from Fars Province, in the southwest of Iran. The responses of biomass and length of coleoptiles to the increasing dosages of the three herbicides were determined in both whole-plant and seed bioassays. In the whole-plant bioassay, all 12 putative resistant populations were found to be resistant to clodinafop with resistance ratios (R/S) ranging from 1.76 to >47.04. Most clodinafop-resistant populations exhibited low levels of cross-resistance to sethoxydim. Three highly sethoxydim-resistant populations, F2, S2, and ES4, were slightly resistant to clodinafop. Six populations (M1, M2, F2, S2, S4, and ES4) showed high cross-resistance to pinoxaden with R/S values as large as 10.73 to 40.29. A highly clodinafop-resistant population, M2, was more sensitive to pinoxaden than the susceptible population. The results of the seed bioassay resembled those obtained from the whole-plant experiment suggesting seed bioassay as an inexpensive, rapid method for screening-resistant genotypes. 相似文献
19.
Sulfonylurea resistance in Stellaria media [L.] Vill. 总被引：1，自引：1，他引：1
A sulfonylurea resistant biotype of common chickweed (Stellaria media L. Vill.) was found in a field treated with chlorsulfuron or metsulfuron for eight consecutive years. In pot experiments the biotype was resistant to postemergence treatments with the following acetolactate synthase (ALS) inhibitors: chlorsulfuron, metsulfuron, tribenuron, triasulfuron, rimsulfuron, sulfometuron, flumetsulam and imazapyr. The level of resistance to chlorsulfuron and sulfometuron was higher than to the other sulfonylurea herbicides. Whereas the level of cross resistance to the triazolopyrimidine herbicide, flumetsulam was comparable to that of metsulfuron, that of imazapyr was significantly lower. In contrast to imazapyr the biotype was not resistant to imazethapyr, an other imidazolinone herbicide. ALS in vitro assays revealed that resistance was due to an ALS enzyme that was less sensitive to ALS inhibiting herbicides. Herbicides with different modes of action were equally effective on the susceptible and resistant biotypes. 相似文献
20.
Diversity in root traits of sorghum genotypes in response to Striga hermonthica infestation 
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下载免费PDF全文 Striga hermonthica is a major biotic constraint to agriculture in the lowland areas of Ethiopia where sorghum is a major stable crop. A pot and a field experiment were conducted in 2011 during the rainy season using 10 sorghum genotypes. Each experiment had infested and non‐infested conditions as the main plots and the 10 genotypes as subplots. The aim of this study was to examine the response of root traits of the sorghum genotypes to S. hermonthica infested conditions and to investigate relationships among S. hermonthica, root and growth traits of sorghum genotypes. Sorghum genotypes were categorized in to three groups, that is, low, moderate and high S. hermonthica count groups. Each group showed a differential response to root traits. Low S. hermonthica count groups had significantly lower root length, root length density, root to shoot ratio and root dry weight compared with susceptible groups. In contrast to low S. hermonthica count groups, moderate S. hermonthica count groups had higher root length, root length density, root to shoot ratio and root dry weight. Highly significant and strong relations were observed among root traits of sorghum, indicating that any of the root traits can be used as indicators for resistance. The result indicates different reactions in root traits in the upper soil layer may be useful for genetic improvement of S. hermonthica resistance and tolerance breeding in sorghum. 相似文献