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为了验证异噁草松高效降解菌W2的降解效果,应用气相色谱法检测异噁草松含量,考察了在室内条件下不同培养温度、土壤湿度、原酶液添加量和异噁草松初始添加浓度对酶液降解异噁草松的影响。结果表明：在培养温度为30 ℃、土壤湿度为田间最大持水量的50%、原酶液添加量为2 mL/kg且酶活力为1.066 μg/mL·min的条件下,30 d降解酶对异噁草松的降解率最高,达到81.7%,与添加菌悬液处理和药剂对照相比分别提高了31.0%和58.5%,降解半衰期（12.3 d）比菌悬液和药剂对照分别缩短了16.9 d和68.3 d,而异噁草松初始添加浓度对降解酶的降解效果影响差异不显著。 相似文献
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异噁草松降解酶的定位及酶学性质研究 总被引：1，自引：0，他引：1
对可降解异噁草松的降解菌W2的降解酶进行定位试验,测得其细胞碎片悬浮液、胞外酶和胞内酶对异噁草松的降解率分别为36.28%,8.71%和62.27%,因此确定降解异噁草松的主要活性物质位于降解菌细胞内,属于胞内酶。应用气相色谱法研究异噁草松降解酶的酶学性质,结果表明:最佳酶促反应时间为60min,最佳酶液添加量为0.3mL,最适pH为7.5,最适反应温度为35℃,米氏常数Km=2.668×10-4 mmol/mL,最大反应速率Vmax=0.322×10-4 mmol/min。 相似文献
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为获得能够修复除草剂莠去津污染土壤的高效降解菌,采用摇瓶富集法、平板分离法从莠去津过量使用的土壤中分离得到降解菌SFAD3,通过形态学、生理生化特征观察以及16S rDNA和ITS序列分析进行种类鉴定,测定获得菌株的最适降解条件,并通过土壤接种和盆栽试验验证菌株对莠去津污染土壤的修复作用。结果表明,菌株SFAD3最终被鉴定为门多萨假单胞菌Pseudomonas mendocina,该菌株培养30 d时对污染土壤中50 mg/kg莠去津的降解率可达72.6%;菌株SFAD3在MM液体培养基中最适降解条件为温度37℃、pH 7、莠去津初始浓度6.25 mg/L、接种量2%,对莠去津降的降解率为50.0%～72.2%;与仅有莠去津的处理相比,添加有SFAD3发酵液的处理20 d后芝麻的株高、根长、湿重和干重能够显著恢复,并且该菌对芝麻还具有一定的促生作用。表明降解菌SFAD3在修复莠去津污染土壤方面具有潜在的应用价值。 相似文献
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建立了采用分散固相萃取为样品前处理方法的高效液相色谱-串联质谱(HPLCMS/MS)快速检测玉米中异噁唑草酮及其代谢物DKN的残留的分析方法。样品经乙腈提取,C18吸附剂净化,电喷雾电离、负离子模式采集,多反应监测模式检测,基质匹配标准品外标法定量。结果表明:在0. 005～0. 5mg/L范围内,异噁唑草酮及DKN在玉米等中的质量浓度与对应的峰面积间呈良好的线性关系,其相关系数均0. 992 2。在0. 01～0. 1 mg/kg添加水平下,异噁唑草酮及DKN在玉米、青玉米和秸秆平均回收率为95%～108%,相对标准偏差(RSD)为2%～11%。异噁唑草酮及DKN在玉米等基质中的定量限(LOQ)均为0. 01mg/kg。该方法简便、快速、准确,可用于玉米中异噁唑草酮及DKN的残留检测。 相似文献
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降解菌2N3对被氯嘧磺隆污染土壤的生物修复 总被引：4，自引：0，他引：4
在实验室条件下,研究了高效降解菌2N3(克雷伯氏菌属,Klebsiella sp.)对被氯嘧磺隆污染土壤的修复作用及其影响因素。当土壤中氯嘧磺隆的添加浓度为20 mg/kg,每 1克土壤中2N3的接菌量为1×106个菌体时,第30 d时土壤中氯嘧磺隆的降解率为84.6%,对照仅为13.4%;相同2N3接菌浓度下,当土壤中氯嘧磺隆浓度为100 mg/kg时,其降解率为31.1%。以小麦、玉米、黄瓜为供试作物,在土壤中施加 20 mg/kg的氯嘧磺隆, 当每 1克土壤中2N3的接菌量为1×106个 菌体时,小麦、玉米、黄瓜的出苗率分别为85%,82%和79%,且处理组株高高于对照,表明降解菌2N3具有明显减轻氯嘧磺隆药害的作用。研究表明,人工接种降解菌2N3可提高土壤中氯嘧磺隆的降解率,有效降低其在土壤中的残留。 相似文献
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异噁唑草酮和噻酮·异噁唑是新型?广谱?高活性的土壤处理除草剂?明确异噁唑草酮和噻酮·异噁唑对玉米田杂草的除草活性及对玉米的安全性是该药剂在玉米田应用的重要内容?本文采用温室整株生物测定法研究了两种药剂对玉米田常见杂草的除草活性及对玉米的安全性?结果表明:20%异噁唑草酮悬浮剂和26%噻酮·异噁唑悬浮剂土壤处理对玉米田杂草有较高的除草活性, 两种药剂对各种杂草的GR90均低于田间推荐剂量?20%异噁唑草酮悬浮剂土壤处理对阔叶杂草藜?苘麻?反枝苋和苍耳均有较高的除草活性, GR90均小于54 g/hm 2, 对禾本科杂草狗尾草?马唐?稗和野黍也有较高的除草活性, GR90均小于63 g/hm 2?26%噻酮·异噁唑悬浮剂对阔叶杂草藜?反枝苋?苘麻和苍耳也有较高的除草活性, GR90均小于62 g/hm 2, 对禾本科杂草狗尾草?马唐?稗和野黍也有较高的除草活性, GR90均小于59 g/hm 2?20%异噁唑草酮悬浮剂和26%噻酮·异噁唑悬浮剂土壤处理对玉米的安全性很高, 对玉米和杂草的选择性指数均高于17?异噁唑草酮及其混剂噻酮·异噁唑用药量低?除草活性强?对玉米安全, 是玉米田土壤处理除草剂较为理想的替代产品? 相似文献
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异噁草酮对土壤微生物和土壤酶活性的影响 总被引：2，自引：0，他引：2
本试验检测了异噁草酮处理土壤后土壤中微生物群落数量和土壤酶活性变化,目的在于研究异噁草酮对土壤微生态产生的影响。结果表明:土壤中异噁草酮有效成分浓度为200、500μg/kg和700μg/kg时,促进土壤中细菌和真菌数量增长,该数量在处理7d之内就会明显变化,并且此影响随异噁草酮使用浓度的提高而增强,但异噁草酮对放线菌的数量无显著影响。施用异噁草酮后,土壤酶活性反应程度由高到低的顺序为:转化酶多酚氧化酶过氧化氢酶。本研究中异噁草酮施入土壤后,除对多酚氧化酶有明显抑制作用,且该抑制作用在短时间内可恢复外,对土壤微生物数量和土壤酶活性都有促进作用。 相似文献
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为探究土壤中具有降解氟咯草酮能力的菌株。采用富集法和平板稀释法筛选菌株,采用液相色谱－串联质谱法（LC-MS/MS）检测分析各菌株对氟咯草酮的降解率,结合形态学观察、16S rDNA和ITS测序分析对筛选得到的优势降解菌株进行鉴定,并采用室内生测法对各菌株进行安全性评价。结果表明,从土壤中获得3株优势降解菌株FL-M-2、FL-M-3、FL-G-2,经鉴定分别为紫色紫孢菌Purpureocillium lavendulum、小双胞腔菌属Didymellaceae sp.和小链霉菌Streptomyces parvus;在接种量为5%,28℃、180 r/min振荡培养7 d,对1 mg/L的氟咯草酮的降解率分别为39.63%、72.09%和68.80%,其中菌株FL-G-2降解效果最好,培养14 d后降解率达到84.37%;安全性试验表明,3株菌的发酵液对小麦和油菜幼苗的生长均无明显的抑制作用。本研究为进一步解析菌株降解氟咯草酮作用机理提供了研究基础,也为进一步开展吡咯烷酮类除草剂的降解提供了新的菌株资源。 相似文献
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为明确异噁唑草酮对玉米根际土壤微生物碳、氮及酶活性的影响, 采用田间试验的方法, 以1倍、5倍和10倍田间推荐剂量为供试除草剂剂量, 测定了异噁唑草酮土壤封闭处理对玉米根际土壤微生物量碳、氮及土壤脲酶、过氧化氢酶、蔗糖酶、脱氢酶和中性磷酸酶活性的影响。结果表明:推荐剂量的异噁唑草酮对玉米根际土壤微生物量碳、氮含量无显著影响, 5倍和10倍推荐剂量的异噁唑草酮对玉米根际土壤微生物量碳、氮含量具有抑制作用。推荐剂量的异噁唑草酮对玉米根际土壤脲酶、过氧化氢酶和蔗糖酶影响较小, 5倍和10倍推荐剂量的异噁唑草酮对其具有明显的抑制作用。异噁唑草酮对土壤脱氢酶活性具有抑制作用, 且施用剂量越高, 抑制作用越强。异噁唑草酮对土壤中性磷酸酶活性的影响表现为前期促进, 后期抑制, 且施用剂量越大, 促进或抑制作用越强。研究表明:推荐剂量的异噁唑草酮对玉米根际土壤微生物量碳、氮及土壤脲酶、过氧化氢酶和蔗糖酶活性的影响较小, 但对土壤脱氢酶、中性磷酸酶活性有影响。 相似文献
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Rates of pesticide degradation in soil exhibit a high degree of variability, the sources of which are usually unclear. Combining data from incubations performed using a range of soil properties and environmental conditions has resulted in greater understanding of factors controlling such degradation. The herbicides clomazone, flumetsulam, atrazine, and cloransulam-methyl, as well as the former insecticide naphthalene offer examples of degradation kinetics controlled by coupling competing processes which may in turn be regulated separately by environmental conditions and soil properties. The processes of degradation and volatilization appear to compete for clomazone in solution; sorbed clomazone is degraded only after the solution phase is depleted. Similarly, volatilization of naphthalene is enhanced when degradation has been inhibited by high nutrient levels. Degradation of the herbicide flumetsulam has been shown to be regulated by sorption, even though the compound has a relatively low affinity for the soil. The fate pathway for cloransulam-methyl shifts from mineralization to formation of metabolities, bound residues and physically occluded material as temperature increases. Atrazine degradation in soil may be controlled in part by the presence of inorganic nitrogen, as the herbicide appears to be used as a nitrogen source by micro-organisms. New insight gained from measurement of multiple fate processes is demonstrated by these examples. 相似文献
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16s rDNA文库法分析番石榴果实蝇共生菌组成 总被引：2，自引：0，他引：2
[目的]探索分析番石榴果实蝇[ Bactrocera correcta (Bezzi)]的共生菌组成,为进一步探索共生菌的生理功能以及与宿主的协同进化关系奠定基础.[方法]构建番石榴果实蝇室内种群共生菌的16s rDNA文库,BLAST分析其共生菌的组成以及丰度.[结果]室内雄虫共生菌主要为Pseudomonas aeruginosa和Lactococcus lactis,雌虫共生菌主要为Enterobacter属的细菌.[结论]本研究结果证明番石榴果实蝇存在多种共生菌. 相似文献
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BACKGROUND: Clomazone is a popular herbicide used on California rice fields and exhibits rapid anaerobic microbial degradation (t1/2 = 7.9 days). To test the potential of direct and indirect photolytic degradation as a cofactor in the overall degradation rate, sacrificial time‐series microcosms were amended with water, non‐sterilized soil + water and sterilized soil + water. Clomazone was added to each microcosm, which was then exposed to natural and artificial sunlight over 35 days. Water and acetonitrile extracts were analyzed for clomazone and metabolites via LC/MS/MS. RESULTS: The calculated pseudo‐first‐order degradation rate constants (k) were kwater = 0–0.005 ± 0.003 day?1, ksterile = 0–0.005 ± 0.003 day?1 and knon?sterile = 0.010 ± 0.002–0.044 ± 0.007 day?1, depending on light type. The formation of ring‐open clomazone, a microbial metabolite, correlated with clomazone degradation. Trace amounts of 5‐hydroxyclomazone (m/z = 256 → 125), aromatic hydroxyclomazone (m/z = 256 → 141) and an unknown product (m/z = 268 → 125) were observed. CONCLUSIONS: The photolytic degradation rate depends on both light type and the quality of the chromophores that induce indirect photolysis. Microbial degradation was found to be sensitive to temperature fluctuations. Overall, microbes are shown to be more detrimental to the environmental fate of clomazone than photolysis. Copyright © 2012 Society of Chemical Industry 相似文献
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三种杀菌剂对黄瓜内生细菌群落多样性的影响 总被引：1，自引：0，他引：1
［目的］ 明确农用链霉素、苯醚甲环唑和代森锌对黄瓜内生细菌群落多样性的影响。［方法］ 采用末端限制性片段长度多态性（T-RFLP）技术分析3种杀菌剂对黄瓜根、茎、叶的内生细菌群落多样性的影响。［结果］ 黄瓜根、茎中的内生细菌种群比较丰富,而叶片中则较少。3种杀菌剂处理后,黄瓜茎、叶的内生细菌多样性指数减少,根部则有所升高,处理后1~5 d内生细菌的种群变化达到最大,14 d后趋于稳定。T-RFLP分析得出黄瓜根、茎、叶中优势的T RFs片段有222、283、326 bp,可知拟杆菌门,厚壁菌门,α和β变形细菌是优势种群。在叶片中,经杀菌剂处理后有6个T-RFs片段消失（如151、193、203、243、305 bp和326 bp）,可知变形菌门和厚壁菌门中的一些细菌对杀菌剂比较敏感。［结论］ 农用链霉素对内生细菌的多样性影响最大,苯醚甲环唑次之,代森锌的影响最小。杀菌剂对黄瓜叶片的内生细菌群落作用最为直接。 相似文献
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Intact spinach chloroplasts were used to determine if clomazone, 5-OH clomazone, and/or 5-keto clomazone inhibited the chloroplastic isoprenoid pathway. When isopentenyl pyrophosphate was used as a precursor, neither clomazone nor the clomazone metabolites (5-OH clomazone and 5-keto clomazone) inhibited the formation of products separated by HPLC in the organic phase. However, when pyruvate, a substrate for the first committed step of the pathway, was used as a precursor, both 5-keto clomazone and fosmidomycin reduced the formation of a non-polar product and increased the formation of a polar product in the organic phase. Only 5-keto clomazone, not 5-OH clomazone or clomazone, inhibited the formation of an additional product other than fosmidomycin in the aqueous phase from pyruvate incorporation. In an in vitro assay, 5-keto clomazone inhibited DXP synthase, the enzyme catalyzing the first committed step of the chloroplastic isoprenoid pathway. Therefore, our studies show that neither clomazone nor 5-OH clomazone inhibits the chloroplastic isoprenoid pathway, only 5-keto clomazone does. 相似文献
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甜瓜白粉病内生拮抗细菌的筛选鉴定及其防治效果的研究 总被引：1，自引：0，他引：1
［目的］从高抗白粉病的甜瓜品种植株内分离筛选出对甜瓜白粉病有较好防效的内生拮抗细菌菌株,为甜瓜白粉病生物防治探寻新途径。［方法］ 采用温室盆栽试验和叶盘漂浮法分离筛选有较好防效的内生拮抗菌,并对其进行形态学、生理生化和分子生物学鉴定。［结果］ 从高抗白粉病的甜瓜品种‘MR-1’植株内分离获得31株内生细菌,其中1株内生菌Mg15对甜瓜白粉病盆栽试验防效达到74.3%。在离体叶盘上,经Mg15发酵液处理12 h后白粉菌孢子萌发率仅为9.29%,14 d后产孢量与对照相比降低了60%。扫描电镜观察发现,Mg15发酵液处理后的病菌菌丝皱缩生长,甚至产生畸形。Mg15发酵原液温室防病效果达80.66%。［结论］ Mg15对甜瓜白粉病具有显著防治效果,经鉴定该菌株为枯草芽胞杆菌（Bacillus subtilis)。 相似文献
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BACKGROUND: Late watergrass [Echinochloa phyllopogon (Stapf.) Koss.] is a major weed of Californian rice that has evolved P450-mediated metabolic resistance to multiple herbicides. Resistant (R) populations are also poorly controlled by the recently introduced herbicide clomazone. The authors assessed whether this cross-resistance was also P450 mediated, and whether R plants also had reduced sensitivity to photooxidation. Understanding mechanism(s) of resistance facilitates the design of herbicide management strategies to delay resistance evolution.RESULTS Ratios (R/S) of R to susceptible (S) GR(50) were near 2.0. [(14)C]Clomazone uptake was similar in R and S plants. Clomazone and its metabolite 5-ketoclomazone reduced chlorophyll and carotenoids in S more than in R plants. The P450 inhibitors disulfoton and 1-aminobenzo-triazole (ABT) safened clomazone in R and S plants. Disulfoton safened 5-ketoclomazone only in S plants, while ABT synergized 5-ketoclomazone mostly against S plants. Paraquat was more toxic in S than in R plants.CONCLUSION: Cross-resistance to clomazone explains failures to control R plants in rice fields, and safening by P450 inhibitors suggests that oxidative activation of clomazone is needed for toxicity to E. phyllopogon. Clomazone resistance requires mitigation of 5-ketoclomazone toxicity, but P450 detoxification may not significantly confer resistance, as P450 inhibitors poorly synergized 5-ketoclopmazone in R plants. Responses to paraquat suggest research on mechanisms to mitigate photooxidation in R and S plants is needed. Copyright (c) 2008 Society of Chemical Industry. 相似文献
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复合微生态制剂对黄瓜根际土壤微生物数量和酶活性的影响 总被引：5，自引：0，他引：5
[目的]研究施入复合微生态制剂对黄瓜根际土壤的影响.[方法]采用盆栽试验的方法,对不同生育时期施入复合微生态制剂的黄瓜根际土壤微生物数量及土壤酶活性进行了测定.[结果]与对照相比,在花期施入复合微生态制剂,可使根际土壤细菌和放线菌的数量分别增加27.9％和20.6％,而真菌和尖孢镰刀菌的数量分别减少64.5％和66.7％;可使土壤脲酶、蔗糖酶、中性磷酸酶活性分别提高130.8％、190.5％、123.5％,差异均显著.黄瓜不同生育时期施入复合微生态制剂对过氧化氢酶作用不明显.[结论]本研究在花期施入复合微生态制剂后,在一定程度上,可提高黄瓜根际土壤细菌和放线菌的数量,减少真菌及尖孢镰刀菌的数量,提高土壤脲酶、蔗糖酶和中性磷酸酶的活性. 相似文献