气相色谱法测定番茄中乙烯利的残留量

建立了一种气相色谱法(GC)测定番茄中乙烯利残留的方法。番茄样品经甲醇-盐酸溶液(V/V=95∶5)提取,无水乙醚萃取,重氮甲烷衍生化,采用GC-NPD检测。结果表明:该方法的平均回收率为92.85%~97.59%,相对标准偏差(RSD)为2.79%~4.38%(n=5),乙烯利的最小检出浓度为0.015 86mg/kg。该方法的杂质干扰少,准确性和灵敏度高,能快速测定出番茄中乙烯利的残留量。     

毒死蜱在梨果实不同部位的残留及消解动态

为探明毒死蜱在梨果实不同部位的残留及消解规律,以20 a生鸭梨（Pyrus bretschneideri Rehd.cv.Yali）为试材,于果实生长期在套袋后向整株喷施48%毒死蜱乳油500倍液（有效成分960 mg/L）,分析毒死蜱向果实中的运输及分配规律;于果实成熟期在采收前向果面喷施48%毒死蜱乳油1 000倍液（有效成分480 mg/L）,分析采后毒死蜱在梨果实不同组织中的分布特征。采用乙腈萃取和GC-NPD检测方法,测定不同处理试材中的毒死蜱含量。结果表明,在果实套袋情况下,整株喷施毒死蜱后72 h内果实不同部位（果心除外）毒死蜱含量均呈现先逐渐上升而后下降趋势,其中果柄、果皮和果梗洼中毒死蜱最高含量值及其出现的时间分别为6.66 mg/kg（12 h）、2.42 mg/kg（24 h）和0.09 mg/kg（12 h）,表明套袋果实毒死蜱来源于枝叶运输,经果柄进入果实后易向果皮累积;而未套袋果施药后24和72 h果皮中毒死蜱含量分别为套袋果的12.56和7.29倍,表明套袋可有效降低果实中毒死蜱的残留量。于果实成熟期向果面喷施毒死蜱后7、14和25 d,果皮中毒死蜱残留量分别为15.54、13.70和12.81 mg/kg,占全果含量的100%,而果肉中毒死蜱残留量低于本检测方法的最低检出浓度（0.05 mg/kg）,因此果皮为果实中毒死蜱主要残留部位,且贮藏期果皮中毒死蜱不易向果肉扩散。     

三甲基硅重氮甲烷衍生化-气相色谱法测定水果蔬菜中乙烯利的残留

针对水果蔬菜中乙烯利的残留,建立了三甲基硅重氮甲烷衍生化-气相色谱的分析方法。样品用 V (甲醇) : V (盐酸) = 9:1的溶液提取,无水乙醚萃取,三甲基硅重氮甲烷衍生化15 min,采用气相色谱-质谱法定性,气相色谱仪-火焰光度检测器 (GC-FPD) 检测,外标法定量。结果显示:在0.01~2 mg/L范围内,乙烯利的质量浓度与其对应的峰面积间线性关系良好,相关系数大于0.999 6;此方法检出限为0.01 mg/kg,定量限为0.03 mg/kg;在辣椒、番茄、香蕉、苹果和梨的空白果蔬样品中分别添加0.01、0.1和1 mg/kg 3 个水平下,回收率为93%~102%,相对标准偏差为4.2%~7.3%。该方法准确度和灵敏度高,抗干扰能力强,能准确并快速测定出水果、蔬菜中乙烯利的残留量。     

乙烯利催熟番茄应用现状及对品质的影响

系统分析了山东省8个地市番茄生产中利用乙烯利催熟现状,针对番茄生产中使用乙烯利存在的问题,设计乙烯利对番茄不同的处理方式和处理剂量,探讨乙烯利不同使用方式对番茄成熟和品质的影响。结果表明:涂抹花梗处理方式对番茄成熟品相和品质的影响最小,正常使用剂量情况下Vc含量降低4.35~5.89%,番茄红素含量降低8.77~9.78%,可溶性固形物含量降低2.45~3.17%;随着使用剂量的提高,对番茄成熟品相和品质的影响加大。     

浸果处理后苯醚甲环唑在柑橘贮藏过程中残留量的变化

研究了贮藏期间柑橘中苯醚甲环唑残留量变化与浸果处理药液浓度、贮藏温度和贮藏时间的关系,以及果实不同部位残留水平的差异。柑橘经苯醚甲环唑药液浸泡处理后在常温或低温条件下贮藏,定期取样用丙酮-石油醚(3∶ 1,体积比)提取,气相色谱测定。当添加浓度范围为0.05 ~5.0 mg/kg时,本方法回收率在81.9% ~91.4%之间,相对标准偏差为5.3% ~17.5%,最低检出浓度为0.02 mg/kg。试验结果表明:柑橘中苯醚甲环唑残留水平与药液浓度呈正相关;低温贮藏下柑橘对苯醚甲环唑的吸收低于常温;苯醚甲环唑的残留水平随贮藏时间的延长而下降;橘皮中苯醚甲环唑的残留明显高于橘肉。建议10%苯醚甲环唑水分散粒剂的使用浓度为100 mg/L,其贮藏安全间隔期为21 d。     

异型莎草和鸭舌草种子萌发条件研究

研究了0．1％升汞溶液、不同浓度赤霉素、不同浓度乙烯利在不同浸种时间、不同的培养基质中对异型莎草和鸭舌草种子发芽率的影响。试验结果证明，异型莎草以1／2MS 10mg/kg GA3的固体培养基，50mg/kg乙烯利浸种12h发芽率最高，达96．38％；鸭舌草以Harvais 0．1mg／kg乙烯利的固体培养基，50mg/kgGA3浸种12h发芽率最高，达89．6％。     

乙烯利浸种对甘蔗根系多胺含量和叶片水势的影响

采用3种浓度乙烯利溶液(0、100、200 mg/L)分别对甘蔗新台糖22号(ROC22)、桂糖17号(GT17)和新台糖10号(ROC10)在下种前进行10 min浸种处理,测定根系中的多胺含量、多胺氧化酶活性、叶片水势及土壤含水量的变化。结果发现,在水分胁迫条件下蔗根精胺(Spm)、亚精胺(Spd)、腐胺(Put)大量积累,100、200 mg/L乙烯利浸种处理的ROC22和ROC10蔗根有较高的多胺含量(Spm、Spd、Put),而GT17则有较低的值,并且都有较低的多胺氧化酶活性;同时100、200 mg/L乙烯利浸种处理减缓水分胁迫时蔗叶组织水势的下降程度,尤以200mg/L乙烯利处理效果最好。试验表明乙烯利浸种可提高甘蔗品种的抗旱性。     

杀虫单在甘蓝上的残留安全性研究

采用气相色谱仪(ECD)检测方法,通过田间试验研究杀虫单在甘蓝的不同施药浓度、不同施药次数及不同采收期过程中的最终残留。研究结果表明,甘蓝中杀虫单的残留量都随施药浓度的增加而增加,高剂量(375g/hm2)、低剂量(300g/hm2)施药不同采收期甘蓝中杀虫单的平均残留量分别为0.097mg/kg、0.059mg/kg;不论是高剂量还是低剂量施药,施药三次的残留量比施药两次的残留量稍高,但差异不明显,施药三次、两次不同采收期的甘蓝中杀虫单的平均残留量分别为0.089mg/kg、0.067mg/kg;7d~14d内甘蓝中杀虫单的最终残留变化较大,7d、10d、14d不同采收期的甘蓝中杀虫单的平均残留量分别为0.16mg/kg、0.048mg/kg、0.020mg/kg。从整体数据来看,在合理规范的采收期下,杀虫单的残留量会显著降低至安全期。     

核桃中乙烯利农药残留分析方法

乙烯利,中文通用名为乙烯利,英文通用名为Ethephon,分子式为C_2H_6ClO_3P,是促进成熟的植物生长调节剂,广泛应用于坚果、水果和蔬菜中。通过实验建立了一种乙烯利在核桃中残留的分析方法,用0. 1%甲酸溶液超声振荡提取,C_(18)-SPE柱净化,LC-MS/MS方法对乙烯利在核桃中残留量进行定量分析。结果表明,该方法的定量限为0. 1mg/kg,乙烯利在0. 1～5. 0mg/kg添加水平,回收率为94%～105%,相对标准偏差为0. 82%～2. 64%。该方法的准确性和灵敏度均达到农药残留分析的要求,且实验方法操作简单。     

番茄喷施激素催熟增产的技术及注意事项

目前，用植物生长调节剂催熟番茄比较普遍。但施用方法不当难以发挥调节剂的效应。 1几种催熟剂的使用方法 　　1)2， 4－滴浸花或涂花。该法可使果实提早成熟 6～ 7 d(天，下同 )，提高坐果率 15％～ 17％，一般增产 30％左右。具体方法是将 2， 4－滴药液放在开口小容器中，把半开或刚开的小花放在药液中轻轻地浸一下，或用毛笔、棉球等蘸取药液涂在花朵或花柄上。所用 2， 4－滴药液的浓度，在保护地为 10～ 20 mg/kg，早春露地为 15～ 20 mg/kg，秋番茄为 10～ 15 mg/kg。每朵花只能用 2， 4－滴处理 1次。药液不能沾到其他部位，特别是…     

Factors affecting the activity of ethephon in stimulating seed germination of Striga hermonthica (Del.) Benth.

Ethephon (2-chloroethylphosphonic acid), which generates ethylene, stimulated the germination of pre-conditioned seeds of Striga hermonthica when it was added to the alkaline Gezira clay soil at concentrations of 2.5 to 30 mg kg^?1. As little as 5 min contact with treated soil was enough to stimulate germination. Ethephon in soil did not cause germination of unconditioned seeds for periods of up to 12 days and also had an adverse effect on seed germination when such seeds were given a second ethephon exposure after a storage period which was adequate, in untreated soil, to give the necessary pre-conditioning. Ethephon activity persisted in air-dry soil but declined over a 14 day period in moist soil. In the field ethephon at 0.6 to 4.8 kg ha^?1 decreased the number of Striga shoots and increased sorghum height and flowering.     

Effects of pre‐ and post‐treatment with ethephon on gum formation of peach gummosis caused by Lasiodiplodia theobromae

Peach gummosis, caused by Botryosphaeria spp. fungi, is the process of gum accumulation and exudation in plants. Ethephon (2‐chloroethylphosphonic acid) has profound effects on plants, including enhanced production of secondary metabolites and regulation of plant diseases. This study investigates the effects of application of ethephon before and after inoculation with Lasiodiplodia theobromae on gum formation. Gum formation was promoted by ethephon treatment prior to pathogen inoculation, but inhibited by ethephon applied after the pathogen. The inhibitory effect was counteracted by 1‐methylcyclopropane, which is an ethylene signal inhibitor. 1‐methylcyclopropane also promoted gum formation. Exposure of three isolates of Botryosphaeria to ethephon inhibited mycelial growth. Both treatment methods increased the sugar content at 12 and 24 h post‐inoculation (hpi). However, the sucrose, glucose and fructose contents were significantly higher in shoots with ethephon post‐treatment (application of ethephon after the pathogen inoculation) than those in shoots with ethephon pre‐treatment (application of ethephon prior to pathogen inoculation) at 48 and 72 hpi. The expression of two putative senescence‐related genes, SEN2 and SEN4, were significantly enhanced in pre‐ and post‐treated shoots with ethephon at 24, 48 and 72 hpi. Ethephon application also up‐regulated expression of the pathogenesis‐related protein PR4 while down‐regulating PR1a and PR10. The results show that ethephon has a dual function in regulating gum formation by affecting both the peach shoots and the pathogen.     

Residues of methomyl in strawberries,tomatoes and cucumbers

An accurate and rapid high performance liquid chromatography method was developed to monitor residues of methomyl in plant extracts. The rate of disappearance of foliage-applied methomyl from strawberries, tomatoes and cucumbers was studied. Residues reached levels of 0.55, 0.2 and 0.6 mg kg^?1 seven days after methomyl had been applied to strawberries, tomatoes and cucumbers, respectively. Results also showed that rinsing treated fruits with tap water removed considerable amounts of methomyl. Samples of strawberries, tomatoes and cucumbers were collected from local markets at Ismailia, and checked for methomyl residues. Residues in 12.5% of tomato and 25% of strawberry samples were above 0.2 mg kg^?1.     

乙烯利体内致突变性研究

为测定乙烯利对人体健康的影响,采用小鼠骨髓细胞微核试验和小鼠精子畸形试验分别检测了乙烯利对小鼠体细胞和生殖细胞的致突变性。3个实验组的微核发生率(6.13‰、9.13‰、11.25‰)与阴性对照组(2.88‰)比较,差异极显著(PP<0.05)。表明乙烯利对体细胞和生殖细胞有致突变性。     

Effects of ethephon pre-treatment on the response of Elymus repens to fluazifop-butyl

Growth inhibition of pot-grown Elymus repens (L.) Gould by fluazifop-butyl was occasionally enhanced by pre-treatment with ethephon. Studies with ¹⁴C-labelled fluazifop-butyl showed that ethephon increased the accumulation of ¹⁴C in basal buds and proximal parts of the rhizome system. This potential modification in the distribution of fluazifop-butyl within E. repens rhizomes may have reduced regeneration and recovery of the E. repens, particularly from the basal buds, although there was no increase in the proportion of ¹⁴C translocated into the rhizome. Also, ethephon not only activated the sinks in the rhizome but in the foliage of E. repens as well, and could initiate buds without sinks. The effects of ethephon on fluazifop-butyl phototoxicity were irregular in their occurrence and degree, and possible reasons for this are discussed. Effets depré-traitements à I'étéphon sur la réponse de Elymus repens au fluazifop-butyl Lors d'expériences en pots, des pré-traitements & 1'étéphon augmentaient occasionnellement 1'inhibition de croissance d'Elymus repens (L.) Gould traité au fluazifop-butyl. Des etudes avec du fluazifop-butyl marqué au ¹⁴C ont montré que l'éléphon augmentait l'accumulation de ¹⁴Cdans les bourgeons de la base et dans les parties proximales des rhizomes. Bien que la proportion de ¹⁴C transportée dans le rhizome ne soit pas accrue, cette modification de la distribution du fluazifop-butyl à l'intérieur des rhizomes d'E. repens pourrait limiter la régénération et la reprise de croissance, en particulier à partir des bourgeons de la base. En outre, l'étéphon activait des puits métaboliques non seulement dans le rhizome mais aussi dans le feuillage d'E. repens et pouvait initier des bourgeons qui ne se comportaient pas comme des puits métaboliques. Tant 1'existence que 1'intensité des effets de 1'étéphon sur la phytotoxicité du fluazifop-butyl étaient irréguliers et les raisons possibles en sont discutées. Wirkung einer Vorbehandlung mit Ethephon auf die Reaktion von Elymus repens (L.) Gould auf Fluazifop-butyl In Gewächshausversuchen war die Wuchshem-mung von Elymus repens durch Fluazifop-butyl gelegentlich durch eine Vorbehandlung mil Ethephon verstärkt. Untersuchungen mil ¹⁴C-Fluazifop-butyl ergaben, daß Ethephon die Ak-kumulation von ¹⁴C in basalen Knospen und proximalen Teilen des Rhizoms förderte. Die so mögliche Veränderung der Verteilung von Fluazifop-butyl in den Quecke-Rhizomen kann zu der reduzierten Regeneration der Pflanzen geführt haben, vor allem aus den basalen Knospen, obwohl insgesamt keine groBere ¹⁴C-Menge im Rhizom gefunden wurde. Ethephon aktivierte nicht nur die Sinks im Rhizom, son-dern auch in den oberirdischen Teilen und kon-nte zur Ausbildung von Knospen ohne Sinks führen. Die Wirkungen des Ethephons auf die herbizide Wirkung des Fluazifop-butyls war unregelmaßig, und die moglichen Grunde dafiir werden diskutiert.     

乙烯利-甲哌 FDA4 复配剂对夏玉米生育及产量的影响

在玉米大喇叭口期叶面喷施乙烯利-甲哌 FDA4 复配剂,能起到改善株型结构、促进同化物分配转运和提高产量的综合效果。具体表现为:1)增加气生根数和根系干重;2)缩短节间长度、增加茎粗,降低株高和穗位高,提高茎粗系数;3)促进灌浆初期同化物向根系分配、灌浆中期在地上部营养器官内积累、灌浆后期向产量器官转运,并有利于玉米提早成熟;4)提高双穗率、增加穗数,减少秃尖、增加行粒数,显著提高玉米单产。上述结果表明,乙烯利-甲哌 FDA4 复配剂能起到防止倒伏、提早成熟的作用,在夏玉米生产中具有较好的应用推广价值。     

Movement and metabolic fate of [14C]ethephon in flue-cured tobacco

The absorption, distribution, and metabolic fate of [¹⁴C]ethephon in flue-cured tobacco (Nicotiana tabacum L.) was studied using autoradiography, thin-layer chromatography, high-voltage paper electrophoresis, and liquid scintillation spectrometry. Labeled ethephon penetrated mature leaf tissue easily and was translocated primarily in an acropetal direction. No ¹⁴C activity was detected in any other plant part except the treated leaf. The first day after treatment, most of the translocated ¹⁴C was detected in the midrib, and after 2 days radioactivity was noticed in veinal areas distal to the point of application. Four days later, however, ¹⁴C was detected in slight amounts only in the midrib, indicating that [¹⁴C]ethephon was rapidly degraded by the leaf tissue. Depending on leaf position on the stalk, as much as 92% of the radioactivity had disappeared from the leaf tissue during the first day after treatment, and as little as 5% of the applied radioactivity was recovered 4 days later. Methanol-extracted plant residues contained insignificant amounts of ¹⁴C. All of the ¹⁴C in methanol extracts was present in the form of a labeled compound with an R_f value corresponding to that of ethephon, indicating the absence of any detectable metabolites of the parent compound. Smoke analysis of cigarettes showed that more [¹⁴C]ethylene than ¹⁴CO₂ was recovered in the main stream, whereas the trend was reversed in the case of side stream smoke.     

Determination of residues of 1-(2-cyano-2- methoxyiminoacetyl)-3-ethylurea (DPX-3217) by gas-liquid chromatography

Residues of the fungicide 1-(2-cyano-2-methoxyiminoacetyl)-3-ethylurea (DPX-3217) in grapes, potatoes, tomatoes and wine were determined by initial extraction with ethyl acetate, clean-up by liquid-liquid partitioning and adsorption chromatography, and final determination by gas-liquid chromatography with a nitrogen-selective detector. The sensitivity of the method was 0.04 mg kg^?1 based on 50-g samples. Recoveries of the compound added to untreated substrates averaged approximately 92% in the range of 0.04-5.0 mg kg^?1.     

A study of ethylene and CO2 evolution from ethephon in tobacco

Buffers and leaf discs of mature tobacco (Nicotiana tabacum L.) were utilized to study [¹⁴C]-ethylene and ¹⁴CO₂ evolution from radiolabeled ethephon, (2-chloroethyl)phosphonic acid. Metabolic fate of [¹⁴C]ethephon in leaf discs was investigated by use of thin-layer chromatography, high-voltage paper electrophoresis, autoradiography, and liquid scintillation spectroscopy. The evolution of labeled ethylene generally increased with increasing buffer pH, buffer volume, and dosage of [¹⁴C]ethephon. [¹⁴C]Ethylene was evolved, increasingly with time, from [¹⁴C]ethephon either added to the buffer or applied to leaf discs. The rate of [¹⁴C]ethylene evolution was maximum during the first day and leveled off on the fourth day. More than 50% of the total [¹⁴C]ethylene evolution over a 96-hr period was recovered during the first 24 hr after [¹⁴C]ethephon application. No ¹⁴CO₂ was evolved when [¹⁴C]ethephon was degraded in the presence of buffer or leaf discs. Only ethephon itself, and no detectable metabolite thereof, was discovered in the methanolic extract of the leaf disc tissue. An insignificant amount of ¹⁴C activity (approximately 2% of the extracted ¹⁴C) was detected in the residue. By means of gas chromatography, it was confirmed that in buffers and tobacco leaf tissue ethephon breaks down to release ethylene but not CO₂.