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1.
以高压汞灯为光源,采用高效液相色谱法研究了纳米TiO2光催化降解毒死蜱的影响因素。结果表明:纳米TiO2的最佳质量浓度为50~100 mg/L;毒死蜱初始质量浓度影响其降解效果,相对较低的质量浓度(5~20 mg/L)下初始浓度与降解率成正相关,相对较高质量浓度(20~80 mg/L)下初始浓度与降解率成负相关;初始质量浓度为10 mg/L时,毒死蜱的降解符合一级反应动力学方程;不同初始pH值的反应溶液经光催化反应后均表现为酸性,碱性条件有利于降解反应的进行。 相似文献
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有机硅表面活性剂和黄原胶对多菌灵和三唑酮在小麦叶片上耐雨水冲刷能力的影响 总被引:1,自引:0,他引:1
为明确有机硅表面活性剂和黄原胶对杀菌剂在靶标作物上行为的影响,采用高效液相色谱分析法,在无降水和模拟降水条件下研究比较了有机硅表面活性剂和黄原胶对多菌灵和三唑酮在小麦叶片上的沉积量和耐雨水冲刷能力,并通过田间小区试验,研究了这两种助剂对多菌灵和三唑酮防治小麦赤霉病效果的影响。结果表明:加入有机硅表面活性剂聚醚聚酯有机硅2230或黄原胶均可提高多菌灵和三唑酮在小麦植株上的沉积量,聚醚聚酯有机硅2230浓度为1.0 mL/L时两种杀菌剂在叶片中的沉积量最高,而黄原胶的最佳用量为20 mg/L。在模拟降雨条件下,加入黄原胶或聚醚聚酯有机硅2230可增强多菌灵和三唑酮耐雨水冲刷能力,提高防治小麦赤霉病的效果。模拟降水2 h,黄原胶浓度为10 mg/L时,多菌灵和三唑酮的淋失率分别从74.26%和81.57%降低到16.0%和28.25%,对小麦赤霉病的防治效果从29.68%和26.39%提高到63.45%和60.98%;添加聚醚聚酯有机硅2230浓度为1 mL/L时,多菌灵和三唑酮的淋失率分别为49.38%和54.67%,防治效果达52.77%和47.83%;但模拟降水6 h时,即使添加助剂多菌灵和三唑酮对小麦赤霉病的防效也较低。 相似文献
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为明确水体中百菌清和丙溴磷的混合光降解行为,利用模拟光源 (高压汞灯) 研究了百菌清和丙溴磷混合水溶液中的光降解作用和光降解产物。结果表明:在高压汞灯照射下,浓度为3 μmol/L的百菌清光降解的半衰期为122.46 min,浓度为3 、6 和9 μmol/L的丙溴磷光解半衰期分别为87.85、86.11和87.63 min。在3 μmol/L的百菌清水溶液中分别添加1、2和3倍 (3、6 和9 μmol/L) 的丙溴磷后,百菌清的光降解半衰期分别降至64.54、38.25和33.05 min,光降解速率分别提高了1.90、3.20和3.71倍;而丙溴磷的光降解半衰期分别为85.57、83.51和84.32 min,降解速率均未发生显著变化。表明丙溴磷对百菌清在纯水中的光降解具有明显的促进效应,且降解速率与丙溴磷浓度呈正相关,而百菌清则对丙溴磷的光降解无影响。百菌清水溶液在单独光降解和加入丙溴磷后,其光降解产物均为4-羟基百菌清;而丙溴磷则产生了5种光降解产物,分别为4-溴-2氯苯基磷酸氢乙酯、O-(4-溴-2-氯苯基)-O-乙基-S-氢磷酸、O-(2-氯苯基)-O-乙基-S-丙基硫代磷酸酯、(2-氯-4-羟基苯基)邻乙基-S-丙基硫代磷酸酯和2-氯-4-溴苯酚。百菌清和丙溴磷的混合水溶液在光照下产生了更多的羟基自由基。该研究可为评估百菌清和丙溴磷复合污染对环境的生态毒性提供重要理论支撑。 相似文献
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采用溶胶-凝胶法制备了二氧化钛/多壁碳纳米管(TiO2/MWCNTs)复合材料,其m(TiO2)∶m(MWCNTs)=3∶4、表面平均孔径为5.724 nm。选用该复合材料对乐果进行光催化降解试验,探讨不同光源及光照时间、乐果初始浓度、复合材料添加量、温度等对其光催化降解能力的影响。结果表明:乐果在25℃、紫外光照30 min、初始质量浓度为5 mg/L和TiO2/MWCNTs复合材料添加量为0.25 g/L条件下的降解率为80.7%,TiO2/MWCNTs复合材料的最大吸附量为16.15 mg/g;在其他条件相同,仅将紫外光改为自然光条件下,乐果的催化降解率为79.2%,与紫外光下的催化降解率相差不大;而同等条件下,Ti O2对乐果在紫外光下的催化降解率比TiO2/MWCNTs低33.1%。因此,可以用自然光代替紫外光用于吸附试验,自然条件下采取该工艺可有效降解环境中乐果污染。 相似文献
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残留的五种有机磷农药在菜豆烹饪过程中的降解 总被引:5,自引:0,他引:5
采用气相色谱法检测了久效磷、毒死蜱、马拉硫磷、对硫磷、敌敌畏5种有机磷农药在菜豆烹饪过程中残留量的变化。结果表明:菜豆经油炸后,除久效磷未降解外,其余农药降解率在37.6%~85.1%之间。油炸时间的长短对敌敌畏降解影响较大,炸5 min时降解率为37.6%,7 min 时降解率为65.2%;油炸时间长短对其余农药的降解均无显著影响。炒的过程中5种农药的降解率在7.6%~56.5%之间;蒸的过程中降解率为23.0%~63.4%;未盖锅盖煮的条件下降解率为39.5%~81.7%,盖锅盖煮后降解率为42.0%~86.4%。在加盖煮10 min后的汤中,各种农药的残留量在0.03~0.50 mg/L 之间。炒过的菜豆再经微波加热2 min后, 5种农药残留量比炒过之后又降解了21.0%~41.5%。 相似文献
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为探究蚜虫共生菌基因组DNA的提取方案,以桃蚜为试验材料,比较了目前较为常用的4种蚜虫基因组DNA提取方法,从DNA纯度、完整性、PCR扩增效率及稳定性等方面进行了比较和评价,并通过调整蛋白酶K用量和水浴温度及时间对STE法进行了优化。结果表明,4种方法提取的蚜虫共生菌基因组DNA均可用于共生菌的PCR扩增检测;CTAB法和SDS法提取的DNA纯度较高,条带较完整,稳定性相对较高,不易降解,而STE法和PCR缓冲液法操作简便,适于快速提取单头蚜虫共生菌的基因组DNA,但纯度相对较低;可根据试验条件和要求进行选择。STE法优化条件为:用30 μL STE缓冲液将蚜虫匀浆,加入1.5 μL 20 mg/mL蛋白酶K,于56 ℃水浴1.5 h;再加入0.1 μL 10 mg/L RNA酶,于37 ℃培养1 h,95 ℃下处理5 min,5 000 r/min离心3 min,将提取到的DNA于-20 ℃保存或直接用于PCR扩增。优化后的STE法可作为提取蚜虫共生菌基因组DNA经济而快捷有效的方法。 相似文献
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表面活性剂辅助-凝固-漂浮分散液-液微萃取-高效液相色谱法检测葡萄酒中4种三嗪类除草剂残留 总被引:1,自引:0,他引:1
建立了表面活性剂辅助-凝固-漂浮分散液-液微萃取-高效液相色谱(SA-DLLME-SFO-HPLC)法检测葡萄酒中西玛津、莠去津、特丁津和扑草净4种三嗪类除草剂残留的分析方法。考察了萃取剂的类型、萃取剂和表面活性剂的体积、萃取时间和盐效应等对萃取效率的影响,确定最佳萃取条件为:20 μL十一醇作为萃取剂,2 μL 0.25 g/L的Tween-20水溶液作为分散剂,萃取时间10 min,氯化钠的质量浓度为250 g/L。结果表明:西玛津、莠去津、特丁津和扑草净的线性范围为0.008~5 mg/L,检出限分别为2.4、1.8、2.0和2.8 μg/L,富集倍数在24.5~32.4之间。在0.008、0.08和2.4 mg/L添加水平下,西玛津、莠去津、特丁津和扑草净在葡萄酒中的回收率在84%~102%之间,相对标准偏差(n=5)在2.1%~6.9%之间。该方法可用于葡萄酒中西玛津、莠去津、特丁津和扑草净残留量的测定。 相似文献
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阿特拉津高效降解菌的分离与筛选 总被引:1,自引:0,他引:1
土样采自河北、山东一些农药厂排污口,通过室内阿特拉津无机盐培养基的驯化培养,分离得到4株在无机盐培养基上对阿特拉津有明显降解圈的降解细菌。底物阿特拉津浓度为1000mg/L,反应体系50ml,体系菌浓度为8.9×107cfu/ml,恒温30℃,180r/min,培养7d,其室内降解效率分别为40.6%、75.7%、82.3%、96.9%。其中菌株BZB-11的降解效率最高。对菌株BZB-11进行降解动态考察,结果显示,BZB-11菌株在无机盐液体培养基中(阿特拉津底物浓度为1000mg/L,反应体系50ml,体系菌浓度6.59×109cfu/ml,恒温30℃,180r/min),对阿特拉津1~3d的降解速度较快,3d可达89.5%,7d的降解率达100%。综合来看,该菌株是一株很有应用前景的高效菌株。 相似文献
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Fenton试剂降解除草剂溴嘧草醚的反应动力学研究 总被引:1,自引:0,他引:1
探讨了Fenton试剂对超高效除草剂溴嘧草醚(ZJ0777)的降解反应。考察了溴嘧草醚、过氧化氢、硫酸亚铁的初始浓度和反应温度等因素对溴嘧草醚降解反应的影响,建立了Fenton试剂降解溴嘧草醚的动力学方程。结果表明:在溴嘧草醚初始浓度分别为0.12和0.24 mmol/L时,达到其降解率90%以上所需的时间分别为32和48 h,而在溴嘧草醚为0.48 mmol/L时,反应84 h只有87%的溴嘧草醚降解;过氧化氢初始浓度在150~300 mmol/L范围内,浓度增加有利于降解反应进行;溴嘧草醚降解反应随亚铁离子浓度的增加而加快(5~20 mmol/L),但过高的亚铁离子浓度对降解反应无效。温度在25~45℃范围内,反应的表观活化能Ea为75.34 kJ/mol。溴嘧草醚的氧化降解符合假一级反应动力学模型。 相似文献
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Experiments were conducted under controlled environmental conditions to study the effects of temperature, duration of wetness, relative humidity (RH) and light on the discharge and germination of ascospores of Venturia nashicola , the causal agent of pear scab in China. Discharge of ascospores from pseudothecia required free water or 100% RH. A period of soaking in water as short as 10 s was sufficient to initiate the discharge of ascospores. Temperatures from 10 to 30°C did not significantly affect the temporal trend of ascospore discharge. A greater proportion of ascospores was discharged under light than in the dark. However, a period of light as short as 10 min, either during the initial wetting of pseudothecia or interrupting the darkness, was sufficient to reduce the inhibitory effect of darkness on ascospore discharge. Ascospores were discharged within 10 min after pseudothecia were wetted and most ascospores ( c. 80%) were discharged within the first hour. The temporal pattern of ascospore discharge could be well described by a logistic model, which estimated that 50% of ascospores were discharged within half an hour of wetting. Ascospores germinated over a wide range of temperatures from 5 to 30°C, with an optimum at c . 20°C. Temporal dynamics of ascospore germination at six temperatures (5, 10, 15, 20, 25 and 30°C) were satisfactorily described by logistic models. 相似文献
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嘧菌酯在水和有机溶剂中的光化学降解 总被引:1,自引:0,他引:1
以500 W氙灯为光源,研究了嘧菌酯在水和有机溶剂中的光化学降解动态及其影响因素。结果表明:当质量浓度为5 mg/L时,嘧菌酯在纯水中光解的半衰期为5.8 h,在2~20 mg/L范围内,其光解速率随初始质量浓度的增大而降低;嘧菌酯在不同介质中的光解速率从大到小依次为乙腈水甲醇正己烷丙酮,其半衰期分别为4.8、5.8、11.5、12.1和23.5 h;硝酸盐对嘧菌酯在水中的光解具有光敏化作用,当NO-3质量浓度为1、2、10和20 mg/L时,其半衰期分别为5.5、5.1、4.5和3.9 h;在1~2 mg/L质量浓度下,NO-2对嘧菌酯在水中的光解具有光敏化作用,而在10~20 mg/L时则表现为光淬灭作用;Fe3+及表面活性剂十二烷基硫酸钠(SDS)对嘧菌酯在水中的光解具有光敏化作用,而腐殖酸和Fe2+则对其表现为光淬灭作用。研究结果可为嘧菌酯的科学合理使用及其环境风险评估提供参考。 相似文献
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Eichhornia crassipes (water hyacinth), a major aquatic weed in India, is one of the targets in a biological weed control research programme in India. A fungal pathogen, Alternaria alternata, is being evaluated as a biological control agent for this weed. The feasibility of solid substrate for the mass production of A. alternata has been examined. Conidia production and virulence of A. alternata were affected by temperature, light and incubation period. The highest number of conidia were produced on rice seed followed by wheat, sorghum, maize seeds and cornmeal at 20°C when exposed to near‐ultraviolet than on the other substrates, while the least conidia were observed on these substrates under light conditions. At 20°C, large numbers of virulent conidia were produced on rice seeds after 4 weeks of incubation under constant dark conditions. Henceforth, the use of rice seeds as a solid substrate for production of A. alternata could be a feasible method to produce conidia in a village co‐operative scenario in India. 相似文献
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K. M. S. Sundaram 《Pest management science》1997,51(1):7-20
The persistence and dissipation behaviour of tebufenozide, an ecdysone agonist, were investigated: (1) under laboratory conditions in aquatic models set up in glass aquaria, and (2) under field conditions in in-situ aquatic enclosures deployed in a mixed-wood boreal forest lake. Two models were set up in the laboratory study (Study I), which was conducted at constant conditions of temperature, water pH and photoperiod. In Model I, partitioning of tebufenozide from sediment, treated at a concentration of 1400 μg kg-1, into untreated water was examined. The results showed that the chemical moved very little from the treated sediment into water. The concentration in sediment and water decreased gradually during the 90-day incubation period. Tebufenozide disappeared faster from the top layer of sediment than from the middle and bottom layers. The half-lives of disappearance were 64 days for the top layer but >90 days for the middle and bottom layers respectively. In Model II, partitioning from water, treated at a concentration of 350 μg litre-1, into untreated sediment was investigated. The results showed that the chemical moved from treated water into sediment due to adsorption. Little vertical downward movement of the adsorbed residues from the top layer of sediment occurred into layers beneath. The adsorbed residues were also not released readily back into water. The concentration in water and sediment decreased gradually during the 90-day incubation period. The half-life of dissipation from water was 67 days. The field microcosm study (Study II), conducted under fluctuating conditions of temperature, water pH and photoperiod, involved application of tebufenozide onto aquatic enclosures at four concentrations of 0·05, 0·10, 0·26 and 0·5 mg litre-1. This study also showed that the chemical moved downwards from the applied location and was adsorbed onto sediment. The chemical persisted longer in Study II than in Study I. Tebufenozide, being photo-labile, probably degraded faster after constant exposure to light in Study I than after exposure to fluctuating light in Study II. At 90 days after treatment in Study I, only about 55% of the applied material persisted in the sediment, and there was little accumulation. In Study II, the material not only persisted but also was accumulated in the sediment, since at 92 days post-treatment the residues were about 25 times higher than the applied concentration level. Residues in water also decreased more rapidly in Study I than in Study II, because the concentration at 90 days post-treatment was about 41% of the applied value. In Study II, however, about 65% of the applied chemical persisted in water at 92 days post-treatment. While the long persistence of tebufenozide in both the laboratory and field studies was attributable to its low vapour pressure, low water solubility, high octanol/water partition coefficient etc., the differences in the persistence characteristics observed in the two studies were due to the fluctuating environmental conditions and water pH encountered in the field study, compared with the constant environmental conditions and water pH utilized in the laboratory study. © 1997 SCI. 相似文献
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KEE WOONG PARK SUNG HWAN CHOI JAE YOUNG AHN YOUNG GEOL SOHN CHANG‐GI KIM JEUNG JOO LEE 《Weed Biology and Management》2011,11(4):235-240
The herbicidal action of clove oil on cucumber seedlings was characterized under light and dark conditions. Paraquat showed herbicidal activity only under the light condition, whereas the clove oil displayed herbicidal activity in both the light and the dark condition. Specifically, wilting and water content reduction progressed rapidly under both the light and the dark condition 1 h after the clove oil treatment, whereas the paraquat damage occurred only under the light condition 5 h after treatment. The malondialdehyde concentration increased more with the clove oil treatment than with the paraquat treatment under the light and dark conditions. The superoxide dismutase (SOD) activity was stimulated, but the catalase activity decreased in the clove oil treatment. In contrast, both the SOD and catalase activity decreased in the paraquat treatment. These results suggest that clove oil exerts herbicidal effects through a mechanism that is different from that of paraquat. 相似文献
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为评价杀虫灯对草地贪夜蛾Spodoptera frugiperda的非直接诱杀效应,在室内观察黑暗、紫色(365~375 nm)、蓝色(460~475 nm)和绿色(490~505 nm)弱光对草地贪夜蛾生殖行为的影响,分析不同光源处理对草地贪夜蛾求偶、交配和产卵行为的影响。结果表明,在第1个暗期内,紫色光源会显著延迟草地贪夜蛾雌成虫求偶开始时间和交配开始时间,而在之后的3个暗期中,紫色、蓝色和绿色光源下草地贪夜蛾雌成虫的交配高峰期较黑暗处理提前,产卵节律没有明显差异;在第1个暗期内,紫色、蓝色和绿色光源下草地贪夜蛾雌成虫的交配时间差异不显著,但在4个连续暗期下,黑暗处理下草地贪夜蛾雌成虫的累计交配时间显著高于其它3种光源处理;黑暗、蓝色和绿色光源下草地贪夜蛾雌成虫的初次交配时间主要集中在第1个暗期,分别占50.00%、50.00%和63.33%,而紫色光源下雌成虫初次交配时间主要集中在第2个暗期,占47.67%;黑暗、紫色、蓝色和绿色光源下草地贪夜蛾雌成虫的交配次数最高分别为5、3、2和3次,交配次数均以1次最多,显著多于其它交配次数;黑暗处理下,各暗期草地贪夜蛾雌成虫交配率之间差异不明显,而在蓝色、紫色和绿色光源下,各暗期之间存在显著差异。表明紫色、蓝色和绿色光源干扰能显著影响草地贪夜蛾的交配行为,其中紫光影响最明显。 相似文献
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Carolina C. Saulle Alexandre Claus Letícia de A. Sales Alan G. Gonçalves Diogo R. B. Ducatti Miguel D. Noseda Louise L. May De Mio 《Plant pathology》2023,72(1):67-75
Grain legume production is of great importance in the world economy, with soybeans being a major agricultural product. Among the main causes of crop losses are diseases caused by pathogens that infect seeds, such as Colletotrichum truncatum, Corynespora cassiicola, Sclerotinia sclerotiorum and Rhizoctonia solani. The fungicides used are not fully effective in controlling these diseases, and new control options are necessary. Photodynamic inactivation (PDI) may be an alternative. PDI consists of the association of a photosensitizer (PS), light and molecular oxygen aimed at the destruction of microbial cells. Porphyrins and their derivatives are aromatic tetrapyrrolic macrocyclic compounds with photosensitizing capacity. The aim of the present study was to evaluate the efficiency of PDI in the photoinactivation of C. truncatum, C. cassiicola, S. sclerotiorum and R. solani, using a mixture of cationic meso-tetra-aryl porphyrins as PS, being the first study to consider this formulation as PS in the photoinactivation of these pathogens. Assays were carried out with soybean seeds artificially inoculated with the different fungi, treated with the PS at 10, 50, 100 and 200 μg/ml and submitted to light under an irradiance of 50 mW/cm2. The assays were set up following the blotter test methodology. The evaluations showed significant reductions in the infection rates of the seeds in relation to the controls. The greatest reductions were 46% for C. truncatum, 95.5% for S. sclerotiorum, 87% for C. cassiicola and 92% for R. solani. The results suggest that PDI can be an important alternative to current control methods against these pathogens. 相似文献
19.
Cleome viscosa is one of the most important weeds of warm‐season crops in southern Iran. Laboratory experiments were conducted to assess the impact of environmental factors on seed germination of C. viscosa . Freshly harvested seeds exhibited dormancy that was relieved (>90%) after immersion for 20 min in concentrated sulfuric acid. Regardless of the temperature regime, the final percentage of germination in light/dark (69.3%) was significantly higher than in complete darkness (58.3%). The optimum temperature for germination was 35/25°C in both light and dark. No germination was observed at constant temperatures of either 15 or 45°C. The thermal thresholds for seed germination, the base (T b) and the mean ceiling germination temperatures (T c(50)) were estimated to be 18.8 and 39.9°C, respectively. A base water potential ( Ψ b(50) ) of ?0.96 MPa was identified for C. viscosa seeds. The response threshold of C. viscosa to reduce 50% of maximum germination for salinity was estimated to be 255 mM. Seeds that were placed on the soil surface had the highest percentage of seedling emergence (77.3%), and no seedlings emerged from seeds placed at a depth of 6 cm. The findings of this study could help to improve the integrated weed management strategies for this species. 相似文献
20.
Bernhard Schick Pran N Moza Klaus Hustert Antonius Kettrup 《Pest management science》1999,55(11):1116-1122
The photolysis of the fungicide vinclozolin in aqueous and methanol–water (50 + 50 by volume) solution has been examined. Irradiation at λ = 254 nm for 10 minutes resulted in <90% and ≤95% substrate transformation respectively. The dissipation of vinclozolin both in water and methanol + water was linear and the calculated half-lives were 1.01 and 2.0 min respectively. Irradiation (8 h) with UV light (λ ≥ 290 nm) resulted in 10% degradation of the chemical, which is of the same magnitude as that of the control (not irradiated). Irradiation (8 h) under artificial sunlight (Suntest) in the presence of commercially available humic acid (K-salt) resulted in 55% degradation of the chemical. Photolysis leads to the opening of the 2,4-oxazolidine-dione ring, forming 3,5-dichlorophenyl isocyanate and 3,5-dichloroaniline. In addition, dechlorination and elimination of the CHCH2 moiety takes place, and one or both the chlorine atoms are replaced by a methoxy group. © 1999 Society of Chemical Industry 相似文献