The photochemical decomposition of the herbicide isoproturon

The photochemical degradation of the herbicide isoproturon in aqueous and non-aqueous solutions and in soils has been investigated. Four new photometabolites were formed in non-aqueous solution and three in soil. These were characterised by spectroscopic methods and identified by comparison with authentic synthetic samples such as 3-(4-isopropylphenyl)-1-methylurea; 3-(4-isopropylphenyl)urea; 4,4′-diisopropylazobenzene and 4,4′-diisopropylazoxybenzene. The pathway of formation of these photo products is depicted.     

PCR方法鉴别大家白蚁和台湾乳白蚁

本文分析了大家白蚁(Coptotermes curvignathus Holmgren)和台湾乳白蚁(C.formosamus Shiraki)形态特征的相似性,并根据GenBank中两者12S rRNA基因序列设计了特异性引物for1、cur2和通用引物com3、com4,通过PCR方法鉴别确认了未知样品为台湾乳白蚁.该方法具有快速、简便、样品量少、准确等优点,适合用于大家白蚁和台湾乳白蚁的鉴别.     

花园葱蜗牛的鉴定及与森林葱蜗牛的鉴别

花园葱蜗牛是我国将修订的进境植物检疫危险性有害生物名录之一，该螺主要分布在欧洲和美国部分地区，我国尚未分布。近年来，我国口岸从欧洲进境的原木和集装箱及箱内货物的木质包装材料中多次截获该种蜗牛，表明该螺入侵的风险较大。现将花园葱蜗牛的检疫截获概况、形态特征、鉴定技术、生物学、传播途径、检疫措施简要介绍如下，供植物检疫工作者参考。     

Inhibition of the photochemical activity of the isolated photosystem ii reaction centre by 2-cyanoacrylates

Certain derivatives of the 2-cyanoacrylates are potent inhibitors of photosystem II (PSII) mediated electron flow. These compounds block electron flow by binding to the D1 polypeptide as do many other types of photosystem II herbicides. In this paper we report the action of these species of 2-cyanoacrylates on the photochemical activity of the isolated PSII reaction centre consisting of the D1 and D2 polypeptides but free of other chlorophyll-binding proteins. The three species tested were 2-ethoxyethyl 2-cyano-3-(4-chlorobenzylamino)-3-isopropylacrylate (cyanoacrylate 1), isopropyl 2-cyano-3-(N-methylanilino)acrylate (cyanoacrylate II) and methoxymethyl 2-cyano-3-(4-chlorobenzylthio)-3-mercapto-acrylate sodium salt (cyanoacrylate III). Unlike the case with thylakoid membranes or PSII enriched membranes, cyanoacrylate III was a more potent inhibitor than cyanoacrylate I of the photoreduction of 2,6-dichlorophenol indophenol (DCPIP) in the isolated PSII reaction centre. This cyanoacrylate was also more effective than diuron (DCMU) in blocking DCPIP reduction in the reaction centre complex. Moreover, unlike DCMU and cyanoacrylates I and II, cyanoacrylate III was more effective in inhibiting the quinone-dependent photoreduction of cytochrome b559 in isolated PSII reaction centres. It is concluded that the hydrophilic nature of cyanoacrylate III gives it greater potency with the isolated reaction centre and that its site of action is likely to be closer to the histidine ligands involved in the binding of non-haem iron rather than in the Q_B binding niche. (See footnote on page 331 for nomenclature of cyanoacrylates).     

Monitoring of the photochemical degradation of metamitron and imidacloprid by micellar electrokinetic chromatography and differential-pulse polarography

The photochemical degradation of metamitron (4-amino-4,5-dihydro-3-methyl-6-phenyl-1,2,4-triazin-5-one) and imidacloprid (1-(6-chloro-3-pyridylmethyl)-N-nitroimidazolidin-2-ylideneamine) has been investigated by differential-pulse polarography (DPP) and micellar electrokinetic chromatography (MEKC); the degradation pathways of these pesticides were elucidated and their degradation products proposed. The electrochemical study of imidacloprid by DPP at different pH values demonstrated the occurrence of two different reduction processes; at pH 6.8, two peaks at −0.90 V and −1.38 V, respectively, were obtained, which are related to the photochemical reduction processes. The photochemical degradation of imidacloprid caused by sunlight was polarographically monitored and its degradation products elucidated. The polarographic reduction of deaminometamitron (obtained by photochemical reduction of metamitron) yielded two peaks at −0.62 and −1.37 V, which are related to the reduction of the CN bonds. The effect of sunlight on the reduction of metamitron was monitored by DPP, and an increase of the concentration of the degradation products was observed with time. MEKC with UV-visible detection was used to separate the pesticides and the products of their photochemical degradation, which were identified in combination with DPP. © 1999 Society of Chemical Industry     

Identification of resistance to Pratylenchus thornei,P. neglectus,P. penetrans and Ditylenchus dipsaci in Turkish accessions of five wild chickpea species (Cicer bijugum,C. echinospermum,C. pinnatifidum,C. reticulatum and C. turcicum)

Phytoparasitica - Plant-parasitic nematodes feed and reproduce in chickpea roots. Root-lesion nematodes are one of the most important biotic factors to limit chickpea production in the world. The...     

大穗看麦娘与日本看麦娘的DNA条形码鉴定

大穗看麦娘是我国麦田新发生的恶性杂草,与日本看麦娘苗期形态相近,导致难以识别和有效监测.本研究利用4个DNA条形码候选序列(rbcL、matK、trnH-psbA和ITS2)对13份大穗看麦娘和10份日本看麦娘叶片材料进行分子鉴定,采用Vector NTI分析扩增的DNA序列峰图质量并比对碱基差异,通过MEGA 6.0...     

Demodex kutzeri sp. n. (Acari: Demodicidae), an identical parasite of two species of deer, Cervus elaphus and C. nippon pseudaxis

Reports on demodicid mites of the old world species of deer are reviewed and Demodex kutzeri sp. n. (= D. cervi sensu Kutzer and Grünberg 1972; part.) described in all stages of the life cycle. The occurrence of D. kutzeri on two host species, Cervus elaphus L., 1758 and C. nippon pseudaxis Eydoux et Souleyet, 1841 is reported and discussed as a rare phenomenon in the genus Demodex.     

Litter decomposition and C and N dynamics as affected by N additions in a semi-arid temperate steppe,Inner Mongolia of China

Litter decomposition is the fundamental process in nutrient cycling and soil carbon（C） sequestration in terrestrial ecosystems. The global-wide increase in nitrogen（N） inputs is expected to alter litter decomposition and,ultimately, affect ecosystem C storage and nutrient status. Temperate grassland ecosystems in China are usually N-deficient and particularly sensitive to the changes in exogenous N additions. In this paper, we conducted a 1,200-day in situ experiment in a typical semi-arid temperate steppe in Inner Mongolia to investigate the litter decomposition as well as the dynamics of litter C and N concentrations under three N addition levels（low N with 50 kg N/（hm2？a）（LN）, medium N with 100 kg N/（hm2？a）（MN）, and high N with 200 kg N/（hm2？a）（HN）） and three N addition forms（ammonium-N-based with 100 kg N/（hm2？a） as ammonium sulfate（AS）, nitrate-N-based with 100 kg N/（hm2？a） as sodium nitrate（SN）, and mixed-N-based with 100 kg N/（hm2？a） as calcium ammonium nitrate（CAN）） compared to control with no N addition（CK）. The results indicated that the litter mass remaining in all N treatments exhibited a similar decomposition pattern： fast decomposition within the initial 120 days, followed by a relatively slow decomposition in the remaining observation period（120–1,200 days）. The decomposition pattern in each treatment was fitted well in two split-phase models, namely, a single exponential decay model in phase I（〈398 days） and a linear decay function in phase II（≥398 days）. The three N addition levels exerted insignificant effects on litter decomposition in the early stages（〈398 days, phase I; P〉0.05）. However, MN and HN treatments inhibited litter mass loss after 398 and 746 days, respectively（P〈0.05）. AS and SN treatments exerted similar effects on litter mass remaining during the entire decomposition period（P〉0.05）. The effects of these two N addition forms differed greatly from those of CAN aft     

Computed effect of decomposition on the partition coefficient determined by the batch equilibration method

A simulation model was used to calculate the effect of decomposition on the soil-water partition coefficient of a herbicide determined by a batch equilibrium method. The results showed the necessity of a correction for decomposition in calculating the equilibrium partition coefficient, especially during repeated desorption steps, even if the amount decomposed was very small. Estimation de l'effet de la déecomposition sur le coefficient de partage déterminé par la méthode de équilibres dans des suspensions Un modèle de simulation a été utilisé pour calculer l'effet de la décomposition d'un herbicide sur son coefficient de partage sol-eau, en déterminant les équilibres dans des suspensions. Les résultats ont montré la nécessité d'une correction pour la décomposition, dans le calcul du coefficient de partage en équilibre, particulièrement durant les étapes de la désorption, et même dans le cas oò les quantités décomposées ont été très faibles. Einfluss des Abbaus auf den Verteilungskoeffizienten-Bestim-mung nach der “batch-equilibration”—Methode Der Einfluss des Abbaus auf die Bestimmung des Boden/Wasser-Verteilungs koeffizienten eines Herbizids mit der “batch-equilibration”—Methode wurde mit einem Simulationsmodell erforscht. Die Ergebnisse ergaben, dass für die Berechnung des Verteilungskoeffizienten eine Korrektur eingeführt werden muss, die dem Abbau Rechnung trägt. Das gilt besonders für wiederholte Desorptionsschritte, auch wenn dabei die abgebaute Menge sehr klein ist.     

Identification of Alternaria spp. on wheat by pathogenicity assays and sequencing

The pathogenicity of Alternaria spp. isolated from wheat leaves collected in regions where alternaria leaf blight has been reported was compared with that of IMI reference isolates of A. triticina and A. alternata using two durum and two bread wheat genotypes. To identify isolates putatively corresponding to A. triticina , morphological and DNA sequence analyses based on ribosomal DNA from the internal transcribed spacer (ITS) region (ITS1, 5·8S rRNA gene, ITS2) and toxicity bioassays of culture filtrate were combined. Glasshouse inoculations provided reliable information to assess the pathogenicity of A. triticina isolates on wheat. Alternaria leaf blight symptoms were produced by the A. triticina isolates only on durum wheat cv. Bansi, while A. alternata , A. tenuissima and A. arborescens isolates were found to be nonpathogenic on the wheat cultivars tested. Alternaria triticina isolates were distinguished from other Alternaria species by Simmons and Roberts' sporulation pattern 6 and two to three conidia per sporulation unit associated with primary conidia bearing long (> 7  µ m) apical secondary conidiophores. Phylogenetic analysis also proved effective at discriminating wheat-pathogenic A. triticina from other nonpathogenic Alternaria species. Alternaria triticina isolates yielded longer ITS sequences than A. alternata , A. tenuissima and A. arborescens isolates, leading to clear-cut differences as visualized with agarose gel electrophoresis. Additionally, only culture filtrates of A. triticina isolates caused nonspecific necrotic lesions on leaves of 3-week-old wheat plants.     

Control of Fusarium wilt in carnation grown on rockwool by Pseudomonas sp. strain WCS417r and by Fe-EDDHA

In carnations grown on rockwool disease incidence of fusarium wilt caused byFusarium oxysporum f.sp.dianthi (Fod) was reduced when Fe-EDDHA instead of Fe-DTPA was used as iron source in the nutrient solution. Addition ofPseudomonas sp. strain WSC417r intensified this reduction in the cultivar Pallas, moderately resistant to Fusarium, but not in the susceptible cultivar Lena. Treatment of plants with Fe-EDDHA instead of Fe-DTPA as iron source resulted in higher numbers and percentages on the roots, ofin vitro antagonistic fluorescent pseudomonads. However, differences were only significant at 56 days after planting for cv. Lena and at 14 and 28 days after planting for cv. Palas. Both chelators, at different concentrations, had no effect on root colonization by eitherPseudomonas sp. strain WCS417r orFod strain WCS816. However, when coinoculated, reduced numbers of propagules ofFusarium were found at concentrations of Fe-EDDHA lower than 10^–5 M.Higher concentrations of the siderophore fusarine produced byFod strain WCS816 were demonstrated when Fe-EDDHA instead of Fe-DTPA was used as iron source in culture media. At equal concentrations, no such differences were found in the amount of siderophore produced by WCS417r. Germ tube length ofFod was less with Fe-EDDHA than with Fe-DTPA. The reduction of germ tube length was stronger when the purified siderophore of WCS417r was added in excess to the culture media with Fe-EDDHA than those with Fe-DTPA. Therefore, the observed reduction of germ tube growth can not completely be explained by iron deprivation. It appeared that EDDHA exhibited a toxic effect for conidia ofFod strain WCS816 as well.we conclude that the observed disease reduction by Fe-EDDHA is a consequence of a limitation of iron availability forFod. This limitation is possibly intensified by the increase in number or percentage of antagonistic fluorescent pseudomonads that strongly compete for iron. The additional effect after bacterization withPseudomonas strain WCS417r in Fe-EDDHA treated carnations of cv. Pallas is likely to be due, at least partly, to a direct competition for iron between the siderophores ofFod strain WCS816 and ofPesudomonas sp. strain WCS417r.Samenvatting Verwelkingsziekte in anjers op steenwol, veroorzaakt doorFusarium oxysporum f. sp.dianthi (Fod), werd gereduceerd indien het ijzer-chelaat Fe-EDDHA in plaats van Fe-DTPA werd toegevoegd aan de nutriëntenvloeistof. Bacterisatie metPseudomonas sp. stam WCS417r had een additioneel effect bij de matig resistence cultivar Pallas maar niet bij de vatbare cultivar Lena. Toevoeging van Fe-EDDHA in plaats van Fe-DTPA aan planten als ijzerbron resulteerde op de wortels in hogere aantallen en percentages fluorescerende pseudomonaden, diein vitro antagonistisch waren ten opzichte vanFod. De verschillen waren echter alleen significant 56 dagen na planten voor de cultivar Lena en 14 en 28 dagen na planten voor de cultivar Pallas. Beide chelaten vertoonden bij verschillende concentraties geen effect op de kolonisatie van de wortel door beide microorganismen. Echter, wanneer beide micro-organismen gezamelijk werden toegevoegd nam de wortelkolonisatie doorFod stam WCS816 af bij concentraties lager dan 10^–5 M Fe-EDDHA. Er werd meer van het siderofoor fusarine doorFod stam WCS816 geproduceerd bij concentraties lager dan 10^–4 M Fe indien Fe-EDDHA in plaats van Fe-DTPA als ijzerbron aan het cultuurmedium was toegevoegd. Er werd geen effect van beide chelaten gevonden op de siderofoorproduktie door WCS417r. Indien een overmaat van het gezuiverde siderofoor van WCS417r werd toegevoegd aan Fe-EDDHA werden een sterkere afname van de kiembuislengte gevonden dan toevoeging aan Fe-DTPA. De reductie van de kiembuislengte bleek niet volledig verklaard te kunnen worden door een afname van de ijzerbeschikbaarheid. Het chelaat EDDHA heeft ook een toxisch effect op conidiën van fusarium.Wij concluderen, dat de waargenomen reductie van de verwelkingziekte door Fe-EDDHA een gevolg is van de afname van de ijzerbeschikbaarheid voorFod. Dit wordt waarschijnlijk versterkt door de ontwikkeling van een antagonistische, fluorescerendePseudomonas-populatie die sterk concurreren om ijzer. Het additioneel effect dat door bacterisatie metPseudomonas sp. WCS417r van de met Fe-EDDHA behandelde matig resistante anjers (Pallas) werd verkregen is voor een deel het gevolg van een directe concurrentie om ijzer tussen de sideroforen vanFod stam WCS816 en vanPseudomonas sp. stam WCS417r.     

Ailinella mirabilis gen. n., sp. n. (eucestoda: pseudophyllidea) from Galaxias maculatus (Pisces: Galaxiidae) in the Andean-Patagonian region of Argentina

Ailinella gen. n. (Pseudophyllidea: Triaenophoridae) is proposed to accommodate Ailinella mirabilis sp. n. from Galaxias maculatus (Jenyns, 1842), a freshwater fish inhabiting the Andean lakes in Argentinean Patagonia. Ailinella belongs to the Triaenophoridae because it has a marginal genital pore, a follicular vitelline gland, and a ventral uterine pore. The new genus can be distinguished from other triaenophorids by the following combination of characters: a small body size, a low number of proglottides, which are longer than wide, a truncated pyramidal to globular scolex, a rectangular apical disc, presence of the neck, lack of internal longitudinal musculature separating the cortex from the medulla, testes distributed in one central field surrounding the ovary laterally and posteriorly, the vagina predominantly anterior to the cirrus sac, vitelline follicles circum-medullary, the genital pores post-equatorial, a saccate uterus, and operculate eggs. Blade-like spiniform microtriches were present on all tegument surfaces, and tumuli on all surfaces of the scolex and the anterior surface of the neck. Microtriches were characterized according to their size and density, and tumuli according to their size, inter-tumulus distance and density. Ailinella mirabilis is the first cestode described from G. maculatus and the second triaenophorid species recorded from a South American freshwater fish.     

近红外光谱法快速测定农药中溴氰菊酯含量

用近红外(NIR)光谱技术结合偏最小二乘法(PLS)进行了敌杀死乳油中有效成分溴氰菊酯含量的快速检测。通过比较敌杀死乳油与常用溶剂的近红外光谱,确定了乳油中使用的溶剂为二甲苯。在敌杀死乳油中加入二甲苯或溴氰菊酯原药来配制不同浓度的校正集,采用PLS建立了有效成分溴氰菊酯的分析模型,模型的决定系数R2、校正标准差(SEC)、交互验证参差均方根(RMSECV)值分别为0.999 9,0.013和0.022。结果表明:近红外光谱技术可以准确测定商品农药制剂中有效成分含量,方法简便、快速,适用于溴氰菊酯制剂的现场、在线分析。     

基于近红外技术柑橘黄龙病田间快速检测方法研究

柑橘黄龙病在感病植株和健康植株之间传播速度快,因此快速检测柑橘黄龙病对其防治十分关键。本文研究了近红外技术快速检测柑橘黄龙病的方法。采用PLS-LDA建立的模型对未参与建模的样品进行了检测,结果表明,该模型检测的准确率与普通PCR检测的结果符合率达到100%,假阳性率小于1%。该技术具有检测周期短、无污染等优点,可用于田间黄龙病的快速检测。     

Revision of the genus Anguillicola Yamaguti, 1935 (Nematoda: Anguillicolidae) of the swimbladder of eels, including descriptions of two new species, A. novaezelandiae sp. n. and A. papernai sp. n

The genus Anguillicola is reviewed on the basis of the examination of some type specimens and other material. Two new species are described: A. novaezelandiae sp. n. from Anguilla australis (type host) from New Zealand and A. anguilla from Italy (conspecific nematodes were originally reported from Italy as A. australiensis) and A. papernai sp. n. from Anguilla mossambica from South Africa. At present the genus Anguillicola comprises the following five valid species: A. globiceps Yamaguti, 1935, A. australiensis Johnston et Mawson, 1940, A. crassus Kuwahara, Niimi et Itagaki, 1974, A. novaezelandiae sp. n., and A. papernai sp. n. Two Anguillicola species, A. crassus and A. novaezelandiae, were apparently introduced in Europe from other continents a few years ago. The genus Anguillicola is divided into two subgenera: Anguillicola (type species A. (A.) globiceps) and Anguillicoloides subgen. n. (type species A. (A.) crassus). All Anguillicola species are briefly described and illustrated. The paper is supplemented by a key to the identification of Anguillicola species.     

Mechanism of action and fate of the fungicide chlorothalonil (2,4,5,6-tetrachloroisophthalonitrile) in biological systems: I. Reactions with cells and subcellular components of Saccharomyces pastorianus

The mechanism and sequence of reaction of chlorothalonil in cells of Saccharomyces pastorianus was investigated by the use of either ¹⁴C-labeled fungicide or Na₂³⁵SO₄-labeled cells. The initial uptake of fungicide resulted in rapid formation of substituted chlorothalonil-reduced glutathione (GSH) derivatives. Chlorothalonil reacted with proteins during derivative formation but decreased cell viability did not occur until all the GSH was reacted and inhibition of specific NAD thiol-dependent glycolytic and respiratory enzymes occurred. It is postulated that enzyme activity and cell viability are controlled either directly or indirectly by the concentration of GSH. The loss of GSH through derivative formation with chlorothalonil and the lack of regeneration of the reduced thiol could be an important feature in the sequence of toxicity of the fungicide. The general mechanism of action of chlorothalonil resembles the trichloromethyl sulfenyl fungicides in that treated cells accumulate large concentrations of fungicide; reactions involve both low and high molecular-weight thiols, with the formation of glutathione-fungicide derivatives; and toxicity resides ultimately with the inhibition of thiol-dependent enzymes.     

树木年轮~(13)C/~(12)C比率记录的树木生长与生态环境关系的研究

树木年轮1 3C/1 2 C对气候的响应是一个复杂的过程 ,气候影响树木的光合作用、呼吸作用等生理过程 ,进而影响树木代谢物质的生成和流动及其同位素的分馏。对树木生长和树轮稳定碳同位素含量与生态环境之间关系的响应的全面分析研究 ,可以更为准确的获得树木年轮同位素1 3C/1 2 C比率与历史气候环境变迁关系的资料。本文在总结前人研究结果的基础上 ,得出以下几点结论 :1 .生态环境决定树木叶片的气孔导通度 ,而导通度又影响植物同化速率 ,进而影响树轮中稳定碳同位素的比率 ;2 .大气CO2 的浓度影响植物对水分的利用效率 ,而植物对水分的利用直接影响树木光合作用的速率 ,进而植物碳同位素比率记录了环境CO2的浓度的变化规律 ;3.植物同化速率和气孔导度与气候要素 ,如温度、湿度、降水、光照及风等气候要素有关 ;4.树木年轮1 3C/1 2 C比率与生态环境的响应的众多研究结果表明稳定碳同位素同环境的相关既存在空间差异也存在树种差异。     

黄瓜绿粉病病原鉴定及其发生规律研究

黄瓜绿粉病是温棚蔬菜上一种新病害,由绿藻门集球藻(Palmellococcus sp.)引起。藻孢卵圆形、长椭圆形、淡绿色、单胞、大小3.39～12.38μm×1.06～10.82μm,表面有山脊状隆起,是一种依附于体表的气生性自养生物。该病害多在1～3月份发生,与湿度密切相关。每日温棚中RH不低于80%,RH100%在12h以上,藻孢生长旺盛;当中午有1h以上RH低于70%时,藻孢的发育受到抑制。凡能增大温棚湿度的栽培措施如灌水、密植等因素均能加重发病。黄瓜品种抗病性无明显差异。     

近红外光谱技术结合支持向量回归法测定嘧菌酯的含量

采用近红外光谱(NIR)技术结合支持向量回归法(SVR)建立了乳油中嘧菌酯的定量分析方法。通过向25%苯醚甲环唑乳油中加入嘧菌酯原药和乙酸乙酯,配制不同浓度的校正集,采用SVR法建立了嘧菌酯的定量分析模型,得模型的决定系数(R2)、校正集均方根误差(RMSEC)、检验集均方根误差(RMSEV)、预测集均方根误差(RMSEP)分别为0.999 7、0.000 9、0.000 9和0.001 7。结果表明,近红外光谱技术结合支持向量回归法可以准确地定量分析乳油中嘧菌酯的含量,方法简单、快捷,在农药市场质量快速监测中具有实际应用价值。