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1.
The degradation in soil of the major constituents of a 1,3-dichloropropene-1,2-dich-loropropane nematicide has been studied under laboratory and outdoor conditions. In sealed glass containers, ( Z)- and ( E)-1,3-dichloropene- 2-14C were converted in soil into the corresponding 3-chloroallyl alcohols and these alcohols were in part strongly bound to the soil. The ( Z)- and ( E)-3-chloroacrylic acids were also found as minor products. More polar products were detected and these released the chloroacrylic acids in 20–30% yield upon hydrolysis. Although the 1,3-dichloropropenes were lost by volatilisation from soil stored in open glass jars outdoors, they also underwent degradation to the same products that were detected in sealed containers. There was evidence of only slight degradation of 1,2-dichloropropane- 2-14C (4 % or less of the applied radioactivity remained unextracted from a loam soil after 5 months). When soil treated with the 1,2-dichloropropane was stored outdoors in an open glass container, less than 1 % of the original radiolabel remained in the soil after 10 days under these conditions due to volatilisation of the applied material. In a separate experiment potatoes were grown in soil 6 months after treatment with a mixture of both ( Z)- and ( E)-1,3-dichloropropene- 2-14C and 1,2-dichloropropane- 2-14C. Although 5 % of the applied radiolabel remained in the soil at potato harvest the potato tubers contained only a very small residue (0.007 mg/kg).  相似文献   

2.
The effects of nine phenoxy-phenoxypropionic acid derivatives and structurally related compounds on the incorporation of [14C]-acetate into free fatty acids in isolated bean and maize chloroplasts were studied. The compounds tested were esters and the corresponding free acids, OH-diclofop, a nonherbicidal metabolite of diclofop in plants, and d and l enantiomers of diclofop. Fatty acid biosynthesis in bean chloroplasts was not affected by all compounds. OH-Diclofop had a weak inhibitory effect on fatty acid synthesis in maize chloroplasts, while free acids were stronger inhibitors than the corresponding esters in the same system. Uptake studies with diclofop-methyl and diclofop indicated that the esters showed higher uptake rates in chloroplasts suspension. d-Diclofop (I50, 9 × 10?8M) was a more potent inhibitor than l-diclofop (I50, 4 × 10?6M). This agrees with the low herbicidal activity of the l enantiomer in vivo. The results suggest that the mode of action in this type of herbicide may be closely linked with the inhibition of fatty acid biosynthesis. The tolerance of beans could be based on an insensitivity of the target site.  相似文献   

3.
The rates at which (E)- and (Z)-mevinphos are hydrolysed in aqueous solutions in the pH range 8.7–11.5, and in the temperature range 30–50°C, have been measured. The overall activation parameters have been calculated, and equations to allow calculation of the rates in any basic conditions are given. The complicated routes by which (E)- and (Z)-mevinphos are hydrolysed to simple molecules have been deduced. The rates for the individual steps in each route have been either measured experimentally, or have been calculated through analogue simulation of all the reactions, by matching the calculated to the observed ultraviolet spectral changes during hydrolysis. It is proposed that (Z)-2-carboxyl-1-methylvinyl dimethyl phosphate is not observed as a hydrolysis product of (Z)-mevinphos because it decomposes by an extremely fast intramolecular reaction. The reasons for the greater lability of (E)-mevinphos are also discussed.  相似文献   

4.
BACKGROUND: The banana moth, Opogona sacchari Bojer, is a polyphagous agricultural pest in many tropical areas of the world. The identification of an attractant for male O. sacchari could offer new methods for detection, study and control. RESULTS: A compound extracted from female O. sacchari elicited responses from antennae of male moths. This compound was identified as a 2/3,(Z)13‐octadecadienal by gas chromatography‐mass spectrometry. An analog, 2/3,(Z)13‐octadecadienol, was also detected in some extracts at roughly a 1:20 ratio (alcohol:aldehyde) but did not elicit responses from antennae of male moths. Electroantennograms of synthetic candidate dienals found the strongest responses from (Z, Z)‐2,13‐octadecadienal and (E, Z)‐2,13‐octadecadienal. In field trials, (E, Z)‐2,13‐octadecadienal attracted more male O. sacchari than (Z, Z)‐2,13‐octadecadienal. Attraction was not improved for either of these compounds when the corresponding stereoisomeric alcohol was added at ratios of 1:1, 1:10 or 1:100 (alcohol:aldehyde). Jackson sticky traps containing 250 µg lures of (E, Z)‐2,13‐octadecadienal caught as many males as did traps holding virgin females. CONCLUSION: (E, Z)‐2,13‐octadecadienal has been identified as an attractant for O. sacchari males and can be used as a monitoring lure of populations of this moth. Copyright © 2010 Society of Chemical Industry  相似文献   

5.
Derivatives of 2‐ethyl‐1,3,4(2H)‐isoquinolinetrione in which the 4‐keto group has been modified to (Z)‐oxime, (E)‐ and (Z)‐O‐methyl oxime, (Z)‐N,N‐dimethyl hydrazone, cyano‐imine and dicyanomethylene moieties have been prepared and evaluated as redox mediator herbicides. All of the compounds have the free‐radical properties required to function as redox mediators, as determined by cyclic voltammetry, though only the O‐methyl oximes, the N,N‐dimethyl hydrazone and the cyano‐imine have reduction potentials in the range required to stimulate the light‐dependent consumption of oxygen at photosystem I in isolated chloroplasts. The O‐methyl oximes and the cyano‐imine are fast‐acting post‐emergence herbicides, producing symptoms of rapid desiccation; the (E)‐O‐methyl oxime is the most active herbicide, being somewhat more potent than the parent isoquinolinetrione. Hydrolysis studies indicate that it is unlikely that any compound generates the parent isoquinolinetrione in vivo. Attempts to explain differences between in vitro and in vivo activities using hydrolytic stabilities and physical properties were unsuccessful, and it was concluded that these factors probably play a less significant role in moderating the herbicidal activity of isoquinolinetrione derivatives than originally thought. © 2000 Society of Chemical Industry  相似文献   

6.
The activity of a number of O-(4,6-dimethoxypyrimidin-2-yl)salicylic acids and their thio analogs inhibiting acetolactate synthase (ALS) preparation was measured. The effects of substituents on the salicylic-benzene ring on the inhibitory activity were analyzed quantitatively with physicochemical substituent parameters. For 6-substituted (thio)salicylic acids, the activity was shown to vary parabolically with the ‘intramolecular’ steric parameter ( Es ). In addition, the higher steric dimension of substituents in terms of the STERIMOL width or length parameter lowered the activity. The field-inductive electron-withdrawing property of the 6-substituents in terms of the Swain–Lupton–Hansch F was favorable for the activity of salicylic acid series. In 5-substituted salicylic acids, the activity was increased by electron-donating substituents with smaller size. The relationships between ALS inhibitory and herbicidal activities were also analyzed with some weed species. Both pre- and post-emergence activities against barnyard grass, Echinochloa crus-galli, were linearly related to the ALS inhibitory activity after allowing for the hydrophobic factor that may contribute to the transport processes. Those against two broad-leaved weed species, Polygonum convolvulus and Abutilon theophrasti were linearly related to the in-vitro activity with no significant participation of the hydrophobic factor. © 1998 SCI  相似文献   

7.
With Beauveria bassiana Lu 700 as biocatalyst an ecologically beneficial process has been developed for the production of (R)-2-(4-hydroxyphenoxy) propionic acid. The fungal strain used in this process, B. bassiana Lu 700, is also a very suitable catalyst for the selective monohydroxylation of other aromatic carboxylic acids.  相似文献   

8.
以乙酰丙酮、溴乙酸乙酯和2,6-二氯吡啶为起始原料,经取代、肼基化、环合、水解、酸化及缩合等反应,得到9个未见文献报道的吡啶联吡唑乙酰基类化合物 B1~B9 。其结构均经核磁共振氢谱和质谱表征。初步生物活性测定表明:在150 g/hm2的处理剂量下,大部分目标化合物表现出一定的除草活性,其中化合物 B2、B3、B6 和 B8 对苘麻Abutilon theophrasti Medicus、反枝苋Amaranthus retroflexus和凹头苋Amaranthus lividus L.生长的抑制率接近100%。  相似文献   

9.
为明确以天然产物阿魏酸为母体进行化学结构改造得到的化合物4-羟基-3-甲氧基肉桂酸乙酯的生物活性及其除草机制,利用茎叶喷雾法和小杯法测定其对马唐和反枝苋的生物活性,基于生理生化指标及功能基因表达量对其除草作用机制进行研究。结果表明:4-羟基-3-甲氧基肉桂酸乙酯对马唐茎叶鲜重抑制中浓度IC50为46.27 mg/L;对反枝苋胚根和芽的IC50分别为129.94 mg/L和147.33 mg/L,且在500 mg/L浓度处理时可抑制反枝苋种子萌发;对拟南芥根长的IC50为43.82 mg/L,在160 mg/L浓度处理时拟南芥几乎停止生长、叶片发黄、根毛堆积。该化合物以1 000 mg/L浓度处理马唐叶片2、3、8 h后,电导率较对照组分别增加了22.70%、18.46%和25.62%;1 000 mg/L浓度处理下叶绿素a/b为2.43,较对照的3.62显著下降;处理后叶表微观结构观察发现化合物浓度越大,植物叶片表皮毛倒伏和褶皱越严重;拟南芥AT4G04820基因表达量显著下降,在处理45 min时下降最显著,与对照组相差42.52倍,微管蛋白含量下降,造成微管解离,从而抑制植物生长。表明4-羟基-3-甲氧基肉桂酸乙酯具有较强的除草活性,可能通过破坏细胞结构、抑制光合作用及阻止根生长等途径使杂草生长受到抑制甚至死亡。  相似文献   

10.
The experimental herbicides 6-chloro-2-trifluoromethyl-imidazo(4,5b)pyridine and 2-t-butyl-6-chloroimidazo(4,5-b)pyridine inhibit the Hill reaction of isolated chloroplasts by 50% at 1.5 and 2.4 pm, respectively. The first compound also uncouples plant and animal oxidative phosphorylation at about 50 pm, whilst the second compound is not an uncoupler, Surprisingly, light does not affect the herbicidal action of either compound on whole plants, so it is unlikely that the herbicidal activity is due to inhibition of the Hill reaction. Since both compounds probably act by the same mechanism, uncoupling of oxidative phosphorylation cannot be the site of herbicidal action, which therefore remains unknown. A study of the metabolism of 6-chloro-2-trifluoromethyl-imidazo(4,5-b)pyridine shows the occurrence of hydroxylation of the pyridine ring in rat and maize and conversion to trifluoroacetic acid in the latter.  相似文献   

11.
1,3‐Dichloropropene (1,3‐D), which consists of two isomers, (Z)‐ and (E)‐1,3‐D, is considered to be a viable alternative to methyl bromide, but atmospheric emission of 1,3‐D is often associated with deterioration of air quality. To minimize environmental impacts of 1,3‐D, emission control strategies are in need of investigation. One approach to reduce 1,3‐D emissions is to accelerate its degradation by incorporating organic amendments into the soil surface. In this study, we investigated the ability of four organic amendments to enhance the rate of degradation of (Z)‐ and (E)‐1,3‐D in a sandy loam soil. Degradation of (Z)‐ and (E)‐1,3‐D was well described by first‐order kinetics, and rates of degradation for the two isomers were similar. Composted steer manure (SM) was the most reactive of the organic amendments tested. The half‐life of both the (Z)‐ and (E)‐isomers in unamended soil at 20 °C was 6.3 days; those in 5% SM‐amended soil were 1.8 and 1.9 days, respectively. At 40 °C, the half‐life of both isomers in 5% SM‐amended soil was 0.5 day. Activation energy values for amended soil at 2, 5 and 10% SM were 56.5, 53.4 and 64.5 kJ mol?1, respectively. At 20 °C, the contribution of degradation from biological mechanisms was largest in soil amended with SM, but chemical mechanisms still accounted for more than 58% of the (Z)‐ and (E)‐1,3‐D degradation. The effect of temperature and amendment rate upon degradation should be considered when describing the fate and transport of 1,3‐D isomers in soil. Use of organic soil amendments appears to be a promising method to enhance fumigant degradation and reduce volatile emissions. Published in 2001 for SCI by John Wiley & Sons, Ltd  相似文献   

12.
Arachidonic acid (AA) is a fatty acid elicitor abundant in the glycerolipids of the late blight pathogen Phytophthora infestans and related Oomycete species. Lipoxygenases (LOX), which catalyze the addition of molecular oxygen to the 1 or 5 position of a cis, cis -1,4- Z, Z -pentadiene system in polyunsaturated fatty acids, is induced in host plants such as tomato and potato during infection by P. infestans. Here it is reported that AA, the LOX metabolites of AA, 5- and 15-hydroperoxyeicosatetraenioc acid (5- and 15-HpETE), and the LOX metabolite of linoleic acid, 9-hydroperoxyoctadecadienoic acid (9-HpODE), are potent inducers of programmed cell death (PCD) in tomato protoplasts. 5- and 15-HpETE increased DNA fragmentation as detected by t erminal deoxynucleotidyl transferase-mediated d U TP-X n ick e nd l abeling (TUNEL) and increased DNA laddering as visualized by ligation-mediated PCR. Background levels of DNA laddering were decreased in intensity by Zn2+ and increased by Ca2+, effects that are consistent with the reported action of these cations on PCD-associated endonucleases in other systems. H2O2, methyl jasmonate, and linoleic and linolenic acids were not toxic to tomato protoplasts at concentrations up to 350 μ , and lipid peroxides (LD100 = 80 μ ) were far more potent inducers of death than free AA within this same concentration range. These results indicate the potential of fatty acid peroxides and LOX-related metabolism to engage an apoptotic type of PCD in higher plant cells.  相似文献   

13.
The recent characterization of triallate-resistant lines of wild oat (Avena fatua L.) deficient in triallate sulfoxidation provides an experimental system to investigate and differentiate the effects of triallate and triallate sulfoxide on wax and lipid biosynthesis. Greenhouse applications of triallate dramatically reduced epicuticular wax deposition in susceptible (S) but not resistant (R) wild oats. Triallate treatment had no effect on in-vivo concentrations of C12 to C26 fatty acids and fatty alcohols in R plants, while elongated fatty acid fractions (C>18) were significantly reduced in S plants. In contrast, treatment with triallate sulfoxide reduced in-vivo concentrations of elongated fatty acids equally in R and S, supporting the hypothesis that triallate sulfoxide is more inhibitory than triallate towards fatty acid elongases. Although de-novo synthesis of short-chain fatty acids was not affected by triallate or triallate sulfoxide in R or S plants, synthesis of elongated fatty acid fractions was dramatically reduced in S plants by triallate. Fatty acid biosynthesis in R and S plants was equally sensitive to triallate sulfoxide. The results support the idea that in-vivo triallate sulfoxidation is necessary for herbicidal activity, and confirm that reduced rates of triallate sulfoxidation confer resistance in R wild oats. © 1997 SCI.  相似文献   

14.
A series of methyl esters of N-substituted (Z)- and (E)-maleamic acids were synthesized and their effect on food intake measured on fifth-instar nymphs of Triatoma infestans. Suppression of food intake was found only for the (Z)-isomers. The initial reaction rate of the synthesized compounds with glutathione (GSH) was calculated from the reaction in vitro of the (Z)-isomers. No reaction was observed with the (E)-isomers. Good correlation between the suppression of food intake, measured by its ED50 (effective dose that inhibited feeding of 50% of the population) and the initial reaction rate with GSH and the hydrophobic parameter π, was found. © of SCI.  相似文献   

15.
阿魏酸衍生物的合成及其除草活性测定   总被引:1,自引:1,他引:0  
为从天然产物中获取新的除草活性成分,通过化学合成的方法对分离自瓜果腐霉Pythium aphanidermatum代谢产物中的阿魏酸进行了结构改造,并采用小杯法,以马唐、马齿苋和播娘蒿为供试杂草对所得化合物进行了除草活性测定。结果显示:所合成的4-羟基-3-甲氧基肉桂酸乙酯、4-羟基-3-甲氧基肉桂酸邻氯苯胺、4-羟基-3-甲氧基肉桂酸酰肼、4-羟基-3-甲氧基肉桂酸叔丁酯和4-乙酰氧基-3-甲氧基肉桂酸5种化合物的回收率分别为96.81%、97.39%、82.20%、75.67%和98.29%。4-羟基-3-甲氧基肉桂酸酰肼和4-乙酰氧基-3-甲氧基肉桂酸对马齿苋胚根的抑制活性最强,IC50分别为87.50 mg/L和74.86 mg/L,其余3种活性相对较弱;4-羟基-3-甲氧基肉桂酸乙酯和4-乙酰氧基-3-甲氧基肉桂酸分别在500 mg/L和1 000 mg/L浓度下可完全抑制播娘蒿和马齿苋胚根、芽的生长,而4-羟基-3-甲氧基肉桂酸邻氯苯胺则在1 000 mg/L浓度下可完全抑制播娘蒿胚根的生长。表明在阿魏酸分子中的不同位点引入适当的基团结构可以提高或者降低阿魏酸分子的除草活性,并获得新的除草活性物质。  相似文献   

16.
Nineteen novel N-acetyl-2,2-dialkyloxazolidines ( 2 ) and N-acetyl-2-alkyl-4,4-dimethyloxazolidines ( 3 ) were synthesized from commercially available carbonyl compounds and ethanolamine or 2-amino-2-methyl-1-propanol. Their bioactivity against laboratory-reared mosquitoes was compared in patch tests to known N-acetyl-2-alkyloxazolidines ( 1 ) and N,N-diethyl-m-toluamide (deet insect repellent). Isomeric composition measurements by [13C]NMR spectroscopy favoured the Z rotational isomer for samples of 2 (91–96% Z) and the E rotational isomer for samples of 3 (66–71% E), in agreement with molecular mechanics calculations on rotational isomers of model oxazolidines. Samples of 1 were previously shown to exist in solution mostly as the Z isomer (60–70% Z). Within the optimal molecular weight range for these experimental chemicals, the duration of repellency against Aedes aegypti (L.), Anopheles quadrimaculatus Say and Anopheles albimanus Wiedemann generally followed the order: 1 > 2 >deet> 3 . Bioassay data are discussed in relation to the equilibrium populations of rotational isomers for substituted N-acetyloxazolidines.  相似文献   

17.
BACKGROUND: Some twig beetles in the genus Pityophthorus (Coleoptera: Scolytinae) may vector pitch canker disease Fusarium circinatum (Niremberg & O'Donnell) of Pinus spp. (Pinaceae). Because Pityophthorus pubescens (Marsh.) has been found to be associated with F. circinatum in the Basque Country (northern Spain), various experiments were conducted to assess the beetle's behavioural responses to (E, E)‐α‐farnesene, (R)‐(+)‐limonene and (S)‐(?)‐verbenone to develop a potential inhibitor to host attraction. These experiments comprise electroantennographic and double‐choice olfactometer tests, as well as field assays in Pinus radiata D. Don stands. RESULTS: Both sexes of P. pubescens showed similar electroantennographic responses to different doses (from 1 ng to 1 µg in decadic steps) of each individual compound, with depolarisations to (S)‐(‐)‐verbenone (100 ng) being similar to those of the aggregation pheromone (+)‐trans‐pityol. In olfactometer assays, both sexes were significantly attracted to (+)‐trans‐pityol, but the attraction was reduced when increasing amounts of the chemicals were added to the pheromone. Particularly relevant was the repellent effect induced by (S)‐(?)‐verbenone at 1 ng dose and higher. In the field, (E, E)‐α‐farnesene, (R)‐(+)‐limonene and (S)‐(?)‐verbenone reduced significantly the number of beetles attracted to (+)‐trans‐pityol and racemic trans‐pityol, with (S)‐(?)‐verbenone being the most effective. CONCLUSIONS: (S)‐(?)‐Verbenone showed an interesting potential for use in the protection of P. radiata stands. A potentially effective strategy, which could be implemented in further, more in‐depth studies, could involve the use of this semiochemical as repellent and (+)‐trans‐pityol‐baited traps as attractant in a ‘push‐pull’ strategy. Copyright © 2012 Society of Chemical Industry  相似文献   

18.
The putrescine analogue. (E)-1,4-diaminobut-2-ene (E-BED), synthesized as the dihydrochloride salt, controlled five economically important crop pathogens, Erysiphe qraminis DC f.sp. hordei Marchal. Uromyces viciae-fabae (Pers.) Schroet, Botrytis fabae Sardina, Podosphaera leucotricha (Ell. & Ev.) Salm. and Phytophthora infestans (Mont) De Bary. The Z-isomer. Z-BED. was also fungicidal, although less so than E-BED. Post-inoculation treatment with E-BED gave greater control of powdery mildew infection on barley and rust and chocolate spot on broad bean than did pre-inoculation application. It was also effective in vitro against Botrytis cinerea Pers. ex Fr., Pyricularia oxyzae Br. & Cav. and Pyrenophora avenae Ito & Karibay. When P. avenae was grown in the presence of E-BED dihydrochloride at 81·5 mg litre?1, growth was reduced by 58% and there were significant reductions in soluble ornithine decarboxylase (ODC) and S-adenosylmethionine decarboxylase (AdoMetDC) activity. These changes were accompanied by a sevenfold increase in putrescine concentration, a 60% increase in spermine concentration and a 32% reduction in spermidine concentration within the fungal tissue.  相似文献   

19.
BACKGROUND: With the objective of exploring the herbicidal activity of substituted aurones, a series of 4,6‐disubstituted and 4,5,6‐trisubstituted aurones were synthesised, and their herbicidal activities against Brassica campestris L. and Echinochloa crusgalli (L.) Beauv. were evaluated in laboratory bioassays. Effects of some of the compounds were evaluated on seed germination. The most active compounds in the laboratory were evaluated in the greenhouse. RESULTS: The compounds were characterised by 1H NMR, 13C NMR and HRMS; some of them were further identified by IR. A (Z)‐configuration was assigned to the aurones, based on spectroscopic and crystallographic data. Bioassay results of root growth showed that the aurones had a moderate herbicidal activity against the dicotyledonous plant Brassica campestris. (Z)‐2‐Phenylmethylene‐4,6‐dimethoxy‐3(2H)‐benzofuranone(6o) was the most active compound, with 81.3 and 88.5% inhibition at 10 and 100 µg ml?1 respectively, equal to the activity of mesotrione. Some of the aurones possessed some inhibition of germination on several plant species. For glasshouse tests, the substituted aurones had lower herbicidal activity than metolachlor and mesotrione. CONCLUSION: It is possible that aurone derivatives, which possess structures different from those of the commercial herbicides, may become novel lead compounds for the development of herbicides against dicotyledonous weeds with further structure modification. Copyright © 2012 Society of Chemical Industry  相似文献   

20.
铜绿丽金龟对寄主植物挥发物的触角电生理及行为反应   总被引:2,自引:0,他引:2  
为深入了解铜绿丽金龟的取食行为,探索开发安全高效的植物源引诱剂,应用昆虫触角电位反应仪和Y型嗅觉仪测试其对不同寄主植物挥发物的趋向行为差异,并根据室内行为结果配制诱剂进行大田试验。结果表明:铜绿丽金龟雄虫对水杨酸甲酯和(1,1’-联环戊基)-2-酮的触角电位反应(electroantennography,EAG)值显著高于其它试剂;石竹烯和水杨酸甲酯能引起雌虫触角较强的电位反应;乙酸顺式-3-己烯酯和石竹烯分别对雄虫和雌虫有较高的嗅觉选择反应率,分别达0.95和0.94。综合EAG和嗅觉试验结果,选择对雌、雄虫均有较好引诱效果的反式-2-己烯醛、乙酸顺式-3-己烯酯、石竹烯、(1,1’-联环戊基)-2-酮和水杨酸甲酯进行田间试验,最终筛选到铜绿丽金龟雄虫的最适引诱剂为每诱芯360 mg乙酸顺式-3-己烯酯,雌虫的最适引诱剂为每诱芯360 mg石竹烯,日诱虫量分别可达33.00±1.53头和29.33±1.45头。  相似文献   

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