苦参碱和苦豆子总碱光分解及光分解抑制的研究

研究了苦参碱(从苦豆子中提取分离获得)和苦豆子总碱在太阳光及紫外光照射下的光分解现象,发现两者均属于光易分解物质,其光分解半衰期均不超过1 h。运用11种不同的光稳定剂处理均能有效地抑制苦参碱和苦豆子总碱光分解,其中以TBHQ(Tertiary-butylhydroquinone,特丁基对苯二酚)的抑制效果最为明显。在此基础上探索了不同浓度TBHQ对苦参碱和苦豆子总碱光分解的抑制效应,结果显示其抑制效果与稳定剂的浓度相关,处理浓度越大,其抑制苦豆子总碱光分解的作用越强。     

Photodecomposition of piperazine in water by ‘sunlight’ ultraviolet radiation

A solution of piperazine in water was photochemically oxidised by the dissolved oxygen when irradiated with ‘sunlight’ ultraviolet radiation obtained with a Hanau Q-300 lamp, or with RUL-300 nm lamps. Sensitisers (riboflavin, acetone and benzophenone) did not increase the rate of the oxidation induced by the RUL-300 nm lamps; however, they (especially riboflavin) accelerated the oxidation induced by the Hanau Q-300 lamp. A large number of products were observed in the sensitised oxidation but they were not analysed further. The irradiation mixture of the non-sensitised photo-oxidation, when 65% of the initial piperazine had been transformed, contained piperazine (35%), glycine (approximately 25%) and three unidentified compounds in equal amounts (approximately 13% each); the same products were obtained with both irradiation systems. The photo-oxidation of piperazine, a metabolite of the fungicide triforine, 1,4-bis(2,2,2-trichloro-l-formamidoethyl)piperaerazine, could thus be a way for the latter's biodegradation at a surface, or in plant tissues, this biodegradation having already been observed.     

乙草胺在水中的光化学降解动态研究

研究了乙草胺在100W中压石英汞灯的光照下的光解动态。结果表明，乙草胺在水溶液中的浓度越高，光解半衰期越长，溶液的pH越高，乙草胺越容易光解。溶液中的溶解氧对乙草胺的光解影响不大，乙草胺在空气饱和溶液中光解速度略快。在不同类型的水中，乙草胺的光解速率也不一样，乙草胺的浓度为20mg/L时，在去离子水，河水和稻田水中的光解半衰期分别为8．06，10．11，12．46min。乙草胺的主要光解产物是羟化乙胺，脱氯可能是乙草胺光解速率的决定步骤。     

On-column degradation and methylation of phenmedipham and desmedipham with N,N, N-trimethylanilinium hydroxide

Phenmedipham and desmedipham, when injected into a gas chromatograph with N, N, N-trimethylanilinium hydroxide, reacted to give derivatives having good gas chromatographic properties. By this procedure, these two carbamate herbicides yielded N-methylated 3-methoxyphenylcarbamates. Maximum methylation was obtained when the molar ratio of methylating reagent to herbicide was approximately 16: 1. This technique for preparing derivatives provided rapid qualitative and quantitative chromatography of the substances examined, without side-chain decomposition. The derivatives obtained were identified by means of ultraviolet, infrared and mass spectrometric procedures.     

Rainfastness and adsorption of herbicides on hard surfaces

Herbicides are still used to control weeds on hard surfaces, including municipal, private and industrial sites. Used under unfavourable conditions, especially when rain occurs shortly after application, herbicides may run off to surface waters. Such losses of herbicides from hard surfaces are estimated to be much higher than for herbicides used in arable fields. In this study, three kinds of hard surface were evaluated: asphalt, concrete surface and gravel (fine and coarse). Three herbicides were applied: glyphosate, diuron and diflufenican. Adsorption isotherms of diuron and diflufenican to the three surfaces were determined. At different times after treatment with the herbicides, rainfall was simulated by use of a rain-droplet spray nozzle, and the run-off was collected for analysis. After this run-off event, the materials were immersed in water to measure desorption which, together with the compound in the run-off, gave a measure of the dislodgable residues. The apolar herbicides diuron and especially diflufenican adsorbed strongly to asphalt. The polar herbicide glyphosate lost 75% in run-off from asphalt but was adsorbed strongly to soil and concrete pavement.     

武汉地区甜菜夜蛾发生动态与气象因子关系初探

采用性诱法、灯诱法及田间调查法对2009-2010年武汉地区甜菜夜蛾成虫、幼虫开展动态监测,结果表明:武汉地区甜菜夜蛾成虫、幼虫主高峰出现在8-10月。根据同时期逐日的气象数据,探讨了武汉地区甜菜夜蛾越冬及成虫高峰日前期气象条件。甜菜夜蛾在武汉越冬虫源存活率低,高温少雨日照多有利于甜菜夜蛾成虫暴发。本研究为进一步探讨甜菜夜蛾在全国范围内迁飞和种群消长提供支撑,为实现基于气象预报的甜菜夜蛾发生测报奠定基础。     

Extended summaries: Pesticides group and physicochemical and biophysical panel symposium: The impact of genetic engineering on pest management. Engineering insect resistance into crop plants

Residue levels of organophosphorus, organochlorine and carbarmate insecticides, urea, carbamate and anilide herbicides, carbendazim, fumigants and bromide were determined in home-grown and imported wheat sampled at UK flour mills during the period February 1987 to December 1988. A total of 764 samples was analysed but not all the wheats were tested for all the residues; 140 of 474 samples examined for organophosphorus insecticides contained residues at levels above the reporting limit, 23 of 119 samples contained residues of gamma-HCH, seven of 104 contained carbon tetrachloride and one of 104 contained 1,2-dibromoethane. No residues of urea, carbamate or anilide herbicides, carbendazim, carbaryl or methyl bromide were detected in 32, 40, 44 and 45 samples respectively. Inorganic bromide levels in 45 samples examined were consistent with natural occurrence. Only a single imported wheat was found to contain a residue (of 1,2-dibromoethane) at a level in excess of UK statutory maximum residue levels.     

Transfer of chlorinated hydrocarbon insecticides and polychlorinated biphenyls from particles to membranes studied by quenching of fluorescence

Hydrophobic chlorinated hydrocarbons are adsorbed onto particles in the environment. Thus, uptake of chlorinated hydrocarbons into organisms is likely to be from the particle-adsorbed state. We investigated the transfer of chlorinated hydrocarbons from particles to phospholipid membranes, quantified by quenching of the fluorescence of a carbazole-labeled phospholipid which was used to label the membranes. The chlorinated hydrocarbons studied included DDT, DDE, methoxychlor, lindane, stirofos, and several polychlorinated biphenyls. The particles studied were porous glass, kaolinite, cellulose, and silica. Transfer of chlorinated hydrocarbons from particles to vesicles was independent of the chlorinated hydrocarbon concentration. The transfer rate did not depend on binding of lipids to particles, and was independent of the lipid composition of the vesicles. Membrane uptake of chlorinated hydrocarbons from the particle-adsorbed state was more rapid than uptake from the microcrystalline state, and uptake was faster when the chlorinated hydrocarbons were dispersed over larger particle surface areas. The transfer rates of chlorinated hydrocarbons correlated with their aqueous solubilities. In total, these results indicate that chlorinated hydrocarbons are transferred through the aqueous phase. We judge the rate-limiting step in membrane uptake to be the rate of solubilization of the chlorinated hydrocarbons from the particles into the bulk aqueous phase. Adsorption of chlorinated hydrocarbons onto particles may enhance the transfer rate by dispersing the chlorinated hydrocarbons and making them more available for solubilization in the bulk aqueous phase. The data are correlated with a model that assumes diffusion across an unstirred aqueous layer which interfaces with the bulk aqueous phase and the particle.     

丙炔 口 恶 草酮在水环境中的降解行为研究

进行了室外大田残留试验,监测了稻田水体中丙炔 口 恶 草酮的消解动态,结果表明,丙炔 口 恶 草酮在稻田水中的消解半衰期为1.2 d。通过室内水解试验及模拟自然光降解试验,研究了丙炔 口 恶 草 酮在稻田水与不同pH缓冲溶液中的水解及光降解规律。在室内25℃避光的田水与pH 5.0 和7.1的缓冲液中,丙炔 口 恶 草酮的降解半衰期均大于90 d,而在pH 9.6的缓冲溶液中的半衰期为3.7 d。在室内25℃及在 4 000±500 lx氙灯光照下,其在田水和pH 7.1、9.6的缓冲溶液中的降解半衰期分别为11.8、13.2和9.8 h。光对水解的显著影响可通过半衰期的长短变化来揭示,表明光照是该药剂在室外田水中迅速降解的一个重要环境因素。     

乙草胺在水中的光化学降解

以高压汞灯、氙灯、自然光为光源 ,研究了乙草胺在不同类型水中的光解动态。结果表明 :乙草胺的光量子产率低 ;高压汞灯光照下 ,乙草胺在水中的光解速度为纯水 >河水 >塘水 >稻田水 ,其光解率与水介质的 pH呈正相关 ;不同光源照射下 ,乙草胺于纯水中的光解速率有显著的差异 ,表现为高压汞灯 >氙灯 >自然光 ,同时其光解产物也存在明显的不同。     

Photolysis of organophosphorus insecticides on soil surfaces

Photolysis on soil surfaces of the organophosphorus insecticides diazinon, methidathion and profenofos was studied under artificial sunlight conditions. All three compounds were readily degraded under the conditions used. The rate of degradation decreased in the order diazinon, profenofos, methidathion and was always greater in moist than in dry soil. The same order of stability was also observed from photolysis studies in aqueous solution. The major photolysis products identified were 2-isopropyl-6-methylpyrimidin-4-ol from diazinon, 5-methoxy-3H-1,3,4-thiadiazol-2-one from methidathion and 4-bromo-2-chlorophenol and 4-bromo-2-chlorophenyl ethyl hydrogen phosphate from profenofos. The same compounds were formed in hydrolysis studies and also upon photodecomposition in aqueous solutions of diazinon and methidathion. Profenofos, however, showed a different photolytic reaction in aqueous systems, forming O-(2-chlorophenyl) O-ethyl S-propyl phosphorothioate. Soil photolysis studies together with hydrolysis experiments could be a useful quick method for obtaining early information on the chemical breakdown products which are to be expected in the soil environment.     

玫瑰黄链霉菌Men-myco-93-63活性代谢产物roflamycoin的光稳定性分析

为研究影响玫瑰黄链霉菌Streptomyces roseoflavus Men-myco-93-63活性代谢产物roflamycoin光不稳定的因素,采用高效液相色谱仪测定了不同光照环境、光照强度、光照时间、溶剂、质量浓度等因素下roflamycoin的光分解率;检测8种光稳定剂对roflamycoin光分解的抑制作用;并通过抑菌圈法测定了光分解前后物质抑菌效果的变化。结果显示,在roflamycoin的光分解过程中,太阳光和日光灯是其敏感光源,而紫外光并不能引起光分解;光照强度越大、光照时间越长、质量浓度越低,其光分解速率越快;在甲醇、丙酮、N,N-二甲基甲酰胺、二甲基亚砜、四氢呋喃5种溶剂中的光分解速率无显著差异;roflamycoin光分解过程最终可以达到一个稳定状态,主要分解为3种物质,并与roflamycoin具有相同的五烯大环内酯骨架;8种光稳定剂均未表现出抑制光分解的作用。roflamycoin光照分解后对12种病原菌仍有抑制作用,其中对番茄灰霉病菌、玉米穗腐病菌等6种病原菌的抑制活性显著增强,抑菌圈直径增大7.64%～21.91%,对棉花黄萎病菌、苹果斑点落叶病菌等4种病原菌的抑制活性显著降低,抑菌圈直径减小10.03%～91.46%。推测roflamycoin的光分解产物仍具有抑菌活性。     

The effect of selected uv absorber compounds on the photodegradation of pyrethroid insecticides applied to cotton fabric screens

UV absorber compounds were tested to reduce the photolytic decomposition of deltamethrin, applied to 100 % cotton fabric, to be used as a target screen for tsetse fly control. In the absence of UV absorbers, over 90% of deltamethrin was degraded after 6 h irradiation under an Osram UV-sun radiation lamp (equivalent to 96 h sunlight) at 35(±1)°C. The degree of protection increased with increase in the proportion of the U V absorber compound. With a mixture of 2,4-dihydroxybenzophenone (I) and deltamethrin (3 + 1, by mass) 7% of deltamethrin was degraded. Similarly, I protected alpha-cypermethrin and cyfluthrin against photolysis, I and 2-hydroxy-4-methoxybenzophenone-5-sulfonic acid (IV) both protected deltamethrin from “Glossinex 200” SC formulation against photolysis, but I was more effective than IV.     

小麦赤霉菌分生孢子产生方法的初步研究

 1.一般赤霉菌在不同培养基上产生的分生孢子较少,但经阳光照射后,其在马铃薯琼脂培养基上产生极多。
2.阳光照射能促进小麦赤霉菌产生大量的分生孢子(每毫升2080万),开培养皿盖照射较关盖照射产生分生孢子的数量稍多,照射时间也缩短一倍以上。赤霉菌经阳光连续照射后,可以不断产生较多的分生孢子。
3.不同光线对赤霉菌产生分生孢子的效用各异。紫外线、日光灯能使其产生分子孢子,红外线和可见光无作用,其中紫外线照射距离17公分,关培养皿盖照射4小时,产生分生孢子最多。
4.赤霉菌经紫外线照射后,温度、湿度、氧气对其产生分生孢子的形态和数量有一定的影响,在处理后3小时就可以形成新的分生孢子。     

The estimation of residue levels of promacyl and its metabolites in beef tissue and fat by high-performance liquid chromatography with electrochemical detection

A method is described for the estimation of residues of the carbamate insecticide promacyl [5-methyl-m-cumenyl butyryl(methyl)carbamate] and its metabolites that are hydrolysable to isothymol (m-cymen-5-ol), using high-performance liquid chromatography with electrochemical detection to determine the isothymol. Clean-up of samples relied on the steam volatility of phenols. Recoveries at the 0.1 mg kg^?1 level varied from 72–88% for fat tissue and 81–91% for liver. The limits of detection were found to be 0.01 mg kg^?1 for and 0.02 mg kg^?1 for liver. A comparative study of the chromatography of sample extracts using both ultraviolet detection and electrochemical detection showed a substantial decrease in the level of interfering co-eluates in the latter method. A field trial, involving a single spray application of the formulated acaricide on milking cattle, revealed residues in the butter fat comparable with those found in a previous investigation.     

Endosulfan residues on alfalfa hay exposed to drying by sunlight,ultraviolet light and air

Endosulfan residues on alfalfa hay exposed to drying by sunlight, ultraviolet light and air under controlled conditions were investigated using g.l.c. and t.l.c. Maximum loss of total endosulfan and related residues calculated as endosulfan occurred approximately 7 days after application and exposure on Lot 1 (dark) and 5 days on Lot II (ultraviolet light) and 6 days on Lot III (sunlight). Maximum losses of residues on Lot I, Lot II and Lot HI were 48.3, 66.7 and 81.9%, respectively. No endosulfan lactone was detected in any of the samples exposed to the different light treatments. In all Lots the endosulfan sulphate percentage of the total residue increased but most dramatically in the dark drying experiment. The endosulfan a-hydroxy ether residues increased in Lot III (sunlight) up to day 7.     

Photochemical transformation of thiophanate-methyl and thiophanate to alkyl benzimidazol-2-yl carbamates

The systemic fungicides thiophanate-methyl (TPM) and thiophanate (TPE) were transformed in aqueous solutions on glass by irradiation with u.v. and sunlight to the more effective fungitoxic substances methyl benzimidazol-2-yl carbamate (MBC) and ethyl benzimidazol-2-yl carbamate (EBC), respectively. The thiophanate fungicides were not converted when incubated in the dark. The photochemical transformation of TPM and TPE to the corresponding alkyl benzimidazol-2-yl carbamates increased with the exposure time of u.v. irradiation. However, no light catalysed reactions occurred when both fungicides were irradiated with u.v. light in the solid state. The residue of TPM and TPE on leaves of cotton plants following spray application were transformed by the energy of sunlight to the more fungitoxic MBC and EBC.     

Evaluation of herbicides for maize production in three ecological zones of Nigeria

Abstract

Maize cultivation in Nigeria has increased rapidly in the last few years as fertilizers have become more readily available to farmers. Without the use of herbicides however, the area of land that can be brought under maize production will be limited. The following herbicides were evaluated in three ecological zones of Nigeria: atrazine and mixtures of atrazine and simazine, atrazine and metolachlor and atrazine and cyanazine. All herbicide treatments were applied at the rate of either 1.0 or 2.0 kg a.i./ha. The plots that received 1.0 kg a.i./ha also received one supplementary hand weeding. All treatments gave yields comparable to the weed free control, with the exception of the unweeded higher rate of the atrazine and cyanazine treatment which gave the lowest grain yield as a result of poor weed control.     

Hydrolysis and photolysis of flumioxazin in aqueous buffer solutions

To determine the degradation rates and degradation products of the herbicide flumioxazin in aqueous buffer solutions (pH 5, 7 and 9), its hydrolysis and photolysis were investigated at 30 degrees C in the dark, and in a growth chamber fitted with fluorescent lamps simulating the UV output of sunlight. The rate of hydrolysis of flumioxazin was accelerated by increasing pH. The t(1/2) values at pH 5, 7 and 9 were 16.4, 9.1 and 0.25 h, respectively. Two degradation products were detected and their structural assignments were made on the basis of LC-MS data. Degradation product I was detected in all buffer solutions while degradation product II was detected in acidic buffer only. Both degradation products appeared to be stable to further hydrolysis. After correcting for the effects of hydrolysis, the photolytic degradation rate also increased as a function of pH and was approximately 10 times higher at pH 7 than that at pH 5, showing t(1/2) values of 4.9 and 41.5 h, respectively. Degradation products formed by photolysis were the same as those formed by hydrolysis. Flumioxazin was degraded more extensively at high pH and should degrade in surface water.     

Photodegradation of bensulfuron-methyl on soil surface

Photolysis of bensulfuron-methyl on soil surface was studied under sunlight and UV light. Seven photoproducts were isolated and characterised by spectroscopic methods. The major processes in the photolysis of bensulfuron-methyl in soil are cleavage of the sulfonylurea bridge, scission of the SO2NH bond and contraction of the sulfuronylurea bridge. The rates of photodegradation of bensulfuron-methyl on different soils followed first-order rate kinetics with half lives of 21.9, 28.4, 36.9, 59.2 and 47.2 h (UV) and 23.1, 27.5, 29.1, 38.9 and 33.8 days (sunlight) for vertisol, alluvial, alfisol, red and laterite soils, respectively. The differences in rates of photodegradation were dependent upon the soil texture and organic matter content.