柑橘全爪螨虫害快速检测仪的研制与试验

为实现在果园现场快速、准确和无损地检测果树受柑橘全爪螨为害程度,该文研制了基于光学测量技术的柑橘全爪螨虫害快速检测仪,并通过试验检验了仪器的使用效果。检测仪采用光反射法,测量果树冠层叶片对红光和近红外光的反射率,根据反射率计算全爪螨为害程度指数作为仪器的输出结果,进而按照无、轻度和重度3个级别判定柑橘全爪螨虫害程度。硬件设计中选取中心波长为665和815 nm的发光二极管阵列作为红光和近红外光源,通过光调制/解调技术、专门设计的光路和光电探测适配电路,克服了自然光线对检测结果的影响。仪器使用效果为:通过标准白板试验确定检测系数k等于2.622;检测结果受树叶密度影响较小;检测结果受自然环境光线影响较小,但气温对检测结果有一定影响;检测仪可区分无、轻度和重度3个级别的全爪螨虫害程度,当虫害程度较低时,检测结果稳定;检测仪输出结果与叶片表面柑橘全爪螨卵数间具有较高的相关性。进一步研究的方向为引入温度补偿的方法以减小温度对检测结果的影响,同时分析当为害程度较严重时结果稳定性较低的原因。     

不同木薯品种对木薯单爪螨的抗性鉴定评价

为了有效满足中国木薯产业健康持续发展需求,系统开展了抗木薯单爪螨木薯品种鉴定与评价。80个参试木薯品种中,C1115和缅甸品种对木薯单爪螨表现为高抗,SC5、SC9、SC15、利民、哥伦比亚4D共5个品种对木薯单爪螨表现为抗,SC8、SC12、SC8002等27个品种对木薯单爪螨表现为中抗,GR10、沙田面包、BRA12等41个品种对木薯单爪螨表现为感,SC205、TMS60444、KU50、面包、BRA900共5个品种对木薯单爪螨表现为高感。取食抗、感品种后的木薯单爪螨发育与繁殖差异显著。与感螨木薯品种相比较,取食抗虫木薯品种后的F0代木薯单爪螨发育历期显著延长（12.67～15.83 d）,F1代每雌产卵量（7.33～14.13粒）、卵孵化率（30.96%～58.23%）和雌成螨比例（61.29%～66.90%）显著降低。上述结果表明,不同品种对木薯单爪螨的抗性不同,抗螨木薯品种可能通过显著延长木薯单爪螨的发育历期及显著降低后代每雌产卵量、卵孵化率和雌成螨抑制了木薯单爪螨种群数量发展,从而表现出抗螨免受木薯单爪螨取食为害。研究结果为深入解析木薯抗单爪螨机理研究提供了参试材料与理论依...     

苯醚甲环唑与吡唑醚菌酯复配对石榴干腐病菌的联合毒力测定

为了明确苯醚甲环唑与吡唑醚菌酯复配组合对石榴干腐病菌的抑制作用,采用生长速率法测定了两种药剂及其不同质量配比组合对该菌的室内毒力,并运用Wadley法评价了复配物的联合毒力作用。结果表明,苯醚甲环唑、吡唑醚菌酯单剂对石榴干腐病菌菌丝生长均有显著抑制效果,其EC50分别为10.21 mg·L^-1和16.48 mg·L^-1;苯醚甲环唑、吡唑醚菌酯复配药剂（质量比分别为1∶1、1∶2、1∶3、1∶4、2∶1、3∶1和4∶1,共7个组合）均表现出了明显的增效作用,尤以2∶1的组合增效作用最强,增效系数（SR）为9.33。     

五种药剂对二斑叶螨的室内毒力测定及田间防效试验

为寻找高效的防螨药剂,增强二斑叶螨的防治效果,避免或减少环境污染和农药浪费,提高种植效益,选择5种药剂对二斑叶螨的室内毒力进行测定。结果表明：螺虫乙酯对二斑叶螨的毒性最强,且持效性最好,可以作为防治二斑叶螨的首选化学药剂。     

辛硫磷农药对刺巴西甲螨体内酶系活性的影响

以刺巴西甲螨作为受试生物,辛硫磷为污染物,采用两个辛硫磷处理时间(48 h和96 h),测定六种酶(乙酰胆碱酯酶、腺三磷酶、谷胱甘肽硫转移酶、过氧化氢酶、谷胱甘肽过氧化物酶、超氧化物歧化酶)的活性随辛硫磷浓度变化的趋势。结果显示了刺巴西甲螨体内酶活性与辛硫磷浓度间存在一定的剂量-效应关系,可为生物指示土壤辛硫磷农药污染提供参考依据。其中乙酰胆碱酯酶和腺三磷酶随辛硫磷浓度增加及处理时间延长表现为抑制效应,而谷胱甘肽硫转移酶、过氧化氢酶、谷胱甘肽过氧化物酶、超氧化物歧化酶的活性总体表现为诱导效应。     

黑土农田土壤甲螨多样性对不同耕作方式的响应

保护性耕作具有保水改土、增产增收和改善生态环境的综合效益,然而目前缺乏其对土壤生物多样性的影响评估。土壤甲螨作为土壤生物的重要组成部分,对土壤环境变化敏感,能够指示土壤健康状况。为阐明土壤动物对保护性耕作的响应,在吉林省农安县保护性耕作试验田,以土壤甲螨为研究对象,比较了常规耕作（CT）、宽窄行免耕（WN）和条带耕作（ST）下土壤甲螨多样性及分布特征。通过形态学鉴定和数量统计,3种耕作方式下共采集土壤甲螨13068头,隶属于24科26属28种。数据分析表明,ST下土壤甲螨个体数和类群数最高。非度量多维标度排序（NMDS）和群落相似性分析（ANOSIM）表明,CT和WN下土壤甲螨群落结构均与ST显著不同;相似性百分比分析表明,CT和WN间土壤甲螨群落差异最大贡献物种为马氏顶甲螨Tectoribates mahunkai,CT和ST间为小上罗甲螨大洋亚种Epilohmannia (Epilohmannia) minuta pacifica,WN和ST间则为尼兰莫小奥甲螨Oppiella（Moritzoppiella）neerlandica。不同耕作方式下土壤甲螨群落beta多样性的主要成分是物种丰富度差异组分（RichDiff）。指示物种分析表明,土壤甲螨可作为农田不同保护性耕作方式的指示生物,其中ST下指示物种共有5种。总体而言,相较于CT和WN,ST更利于增加土壤甲螨密度和丰富度,对黑土区土壤动物多样性保护具有重要意义。     

Comparison of Sampling Techniques for the European Red Mite,Panonychus ulmi (Koch) (Acari: Tetranychidae) and the Apple Rust Mite,Aculus schlechtendali (Nalepa) (Acari: Eriophyidae)

Abstract

Several methods were tested for estimating population size of two phytophagous mites on the apple cultivars Aroma, Summerred and Gravenstein. The washing technique was rated as most efficient for estimating the Panonychus ulmi population. Counting one quarter of the total number of mites in the sample gave a sufficiently precise estimate of the P. ulmi population. The mites are easily washed off and are well preserved for further study. The brushing technique was more efficient than direct counting of Aculus schlechtendali, and is the better way to handle an extensive sampling programme.     

Predicting ESP and SAR by artificial neural network and regression models using soil pH and EC data (Miankangi Region,Sistan and Baluchestan Province,Iran)

Monitoring exchangeable sodium percentage (ESP) and sodium adsorption ratio (SAR) variability in soils is both time-consuming and expensive. However, in order to estimate the amounts of amendments and land management, it is essential to know ESP and SAR variations and values in sodic or saline and sodic soils. Thus, presenting a method which uses easily obtained indices to estimate ESP and SAR indirectly is more optimal and economical. Input data of the current research were 189 soil samples collected based on a regular networking approach from Miankangi region, Sistan plain, Iran. Then, their physicochemical properties were measured. Results showed that SAR = 3.8 × ln(EC) + 22.83 × ln(pH) – 44.37, (R² = 0.63), and ESP = 3.98×ln(EC) + 36.88(pH) – 56.98 (R² = 0.78) are the best regression models for estimating SAR and ESP, respectively. Moreover, multilayer perceptron (MLP), which explains 95–97% of parameters of soil sodicity using EC and pH as inputs, was the best neural network model. Therefore, MLP could be applied for ESP and SAR evaluation with high accuracy in the Miankangi region.     

柑橘溃疡病菌单链二硫键稳定重组抗体的构建、表达和特性

柑橘溃疡病(citrus bacterial canker disease,CBCD)是危害柑橘(Citrus reticulata Blanco)的重要病害,为了给柑橘溃疡病的现场快速诊断提供一种稳定的重组抗体,构建一种快速检测技术,本研究以鼠源抗柑橘溃疡病菌(Xanthomonas axonopodis pv.citri,Xac)表面脂多糖的二硫键稳定性抗体dsFv为模板进行基因改造,利用重叠延伸PCR在其重链可变区(VH)和轻链可变区(VL)之间引入一条人类抗体重链恒定区1(CH1)5'端12个氨基酸的序列作为连接肽,构建重组单链二硫键稳定抗体基因sc-dsFv。将获得的基因连接pET24a(+)载体,转入大肠杆菌(Escherichia coli)BL21(DE3)得到工程菌,IPTG诱导表达。表达产物经体外复性并以Ni-NTA亲和层析对目标蛋白sc-dsFv进行纯化,利用斑点免疫杂交、ELISA和BIAcore检测抗体的活性、稳定性、特异性及亲和力。构建的抗体基因经测序结果表明,抗体重链可变区(VH)和轻链可变区(VL)基因之间成功引入目标连接肽序列,重组sc-dsFv蛋白实现了原核高效表达;通过体...     

Bioactive compounds of grapefruit (Citrus paradisi Cv. Rio Red) respond differently to postharvest irradiation, storage, and freeze drying

In the present study, the effect of irradiation, storage, and freeze drying on grapefruit bioactive compounds was investigated. Grapefruits were exposed to one of two irradiation doses: 0 (control) or 300 Gy (137Cs, a proposed treatment against fruit flies) and then stored for up to 6 days. At the last storage time point (6 days after harvest), grapefruit pulp from control and irradiated fruits was freeze-dried. Bioactive compounds were extracted from Rio Red grapefruit pulp and analyzed with reverse phase liquid chromatography while volatile compounds were analyzed using gas chromatography. Freeze-dried pulp from irradiated fruits had a higher (P < or = 0.05) flavonoid content (naringin and narirutin) as compared to the freeze-dried pulp from the control fruits. Freeze-drying treatment reduced (P < or = 0.05) the lycopene content, but the reduction (P < or = 0.05) in beta-carotene content occurred only in the control fruit. Reduction in d-limonene and myrcene was observed in the irradiated fruits at 6 days after harvest and in the freeze-dried samples. These results warrant testing of the effect of postharvest treatments and processing on bioactive compounds in functional systems as they have varied effects on different bioactive compounds of grapefruit.     

Toxicity interaction of metals (Ag, Cu, Hg, Zn) to urease and dehydrogenase activities in soils

A study of the individual and mixture toxicities of the trace metals Ag, Cu, Hg, Zn to the soil enzymes dehydrogenase and urease was undertaken. An agricultural soil and a sandy forest soil were spiked with metal salts, individually and in combinations. The anion additions to the various treatments and controls were normalized for added anions using Ca salts. The soils were then left to equilibrate and leached to reduce the excess metals and anions. Total and dissolved metal concentrations were measured concurrently in order to consider the effect of soil chemistry on the enzyme activities. Dose-response relationships for total soil metals and soil solution metals were estimated for each metal separately following a log-logistic curve fitting. Ag and Hg were the most efficient metals to reduce soil enzyme activities. The Bliss independence model was used to predict the toxicity of metal combinations. The enzyme responses in relation to the total soil metal combinations were synergistic for the agricultural soil and antagonistic for the forest soil; possibly as a result of a higher organic matter content and higher pH in the latter soil. Enzyme activities expressed in relation to the dissolved metal concentrations were more variable than against the total metal contents and consequently we observed both synergistic and antagonistic interactions.     

The Influence of Water Hardness, pH, and Suspended Solids on Nickel Toxicity to Larval Fathead Minnows (Pimephales promelas)

Nickel (Ni) is an ubiquitous, naturally occurring metalthat is associated with metal mining and other industrialactivities. Despite elevated Ni concentrations reportedfor many industrial receiving waters, Ni receives littleresearch attention addressing factors influencing itstoxicity to freshwater fish. This study examined theinfluence of water hardness, pH, and total suspended solids(TSS) in soft, reconstituted water on Ni toxicity to larvalfathead minnows (Pimephales promelas). Increasingwater hardness from 20 to 140 mg L^-1 (as CaCO₃) reduced acute Ni toxicity by 5-fold (96-h LC50s 0.45 and 2.27 mg Ni L^-1, respectively). Low pH had a slight protective effect against Ni toxicity relative to neutral pH conditions. At pH 5.5, the 96-h LC50 was 0.69 mg Ni L^-1, compared to 0.54 mg Ni L^-1 at pH 7.0. However,Ni toxicity was significantly reduced at pH 8.5 where the 96-h LC50 was 2.21 mg Ni L^-1. These results were explainedon the basis of Ni speciation. Total suspended solids also reduced Ni toxicity (expressed as 96-h LC50s) from 0.35 to 1.12 mg Ni L^-1 over a TSS range of 10 to 100 mg L^-1.This reduction of toxicity due to TSS is significant becausemine effluents often have a combination of elevated TSS andmetals. The ameliorative effect of TSS was not as significantas high hardness or pH probably because there is a TSS threshold, after which physical irritation to fish gills counteracts any protective effect conferred by TSS. This finding is relevant to choices made in design of mine effluenttreatment systems; i.e., there may be an optimum range ofTSS concentrations that protect aquatic biota againsteffects of metals that remain after treatment.     

Influence of Soil Organic Carbon on Acute and Chronic Toxicity of Plant Protection Products to Poecilus cupreus (Coleoptera, Carabidae) Larvae (4 pp)

Background, Aims and Scope   Variability of results from terrestrial ecotoxicological tests with arthropods demonstrate the importance of understanding the impact of soil composition has on the bioavailability of pollutants. Beside other soil parameters, the organic C content is known to be relevant to bioavailability. The aim of the present paper was to detect lethal and sublethal effects of plant protection products on soil-dwelling larvae of the carabid beetle Poecilus cupreus under different concentrations of soil organic C. The study was based on a familiar laboratory test method. Methods   Larvae of the laboratory-reared carabid beetle P. cupreus were exposed to dimethoate in a standardised soil (Lufa 2.1), modified to four different concentrations of organic C between 0.5 to 2.8% by admixing peat. Dimethoate was applied to the soil surface at rates ranging between 40 and 250 g a.i./ha. Some larvae were exposed to an application of water to act as a control. One larva was released per test tube, with at least 20 larvae per treatment group. Effects on mortality and developmental time of the larvae and on the hatching weight of adult beetles were recorded. Dimethoate was selected as the test item because some dose-response data for different soils were already available and because the reproducibility of test results with dimethoate had already been shown in a previous ring test. Results and Discussion   With increasing concentration of organic C in the soil substrate, mortality decreased at all tested rates of dimethoate. Consequently, LC50 values increased from 39 to 107 g a.i./ha with increasing organic C content from 0.5 to 2.8%. The results suggest higher bioavailability of dimethoate with decreasing content of organic C. The replication and magnitude of sublethal effects (hatching weight and developmental time) was insufficient to detect a clear interaction between dimethoate and organic C. Conclusion   The results of the experiment reveal that the concentration of organic C in the soil substrate is influential on the effects and, by association, the toxicity of dimethoate to larvae of P. cupreus. For the interpretation of terrestrial ectotoxicological tests with arthropods, the composition of the substrate has to be taken into account. Recommendations and Outlook   For reliable and reproducible test results, a well-defined and thoroughly controlled composition of the test soil is highly recommended. Test results should be used for risk assessments only after having taken the soil composition, especially the organic C content, into account.     

Toxicity of Sb and Cu in Sewage Sludge to Terrestrial Plants (Lettuce,Oat, Radish), and of Sludge Elutriate to Aquatic Organisms (Daphnia and Lemna) and its Interaction

Antimony (Sb) and Copper (Cu) are two metals of major concern in sewage sludge. Antimony because its use in society is increasing and this might lead to increased Sb concentrations in sludge. Copper because its total volume in use in society is large and because of corrosion from water pipes it is most difficult to reduce the Cu concentrations in sludge. Fresh digested sewage sludge was spiked with Cu or Sb and the sludge was cultivated with oat (Avena sativa), lettuce (Lactuca sativa) or radish (Raphanus sativus). Elutriates from the cultivated sludge were tested for toxicity with Lemna minor (7-d growth) and Daphnia magna (48 h immobility). Before cultivation the elutriates were toxic to Lemna and Daphnia due to high concentrations of ammonia (NH₃) and nitrite (NO₂ ^-). Cultivation decreased the concentrations of both NH₃ and NO₂ ^-, thereby reducing the impact of these compounds in the toxicity tests. Cultivation also decreased the metal concentrations and pH. Daphnia magna was the most sensitive test organism in this study with a 48 h EC₅₀ of 1130 mg Cu kg^-1 dry wt and 5 mg Sb kg^-1 dry wt in elutriates from sludge cultivated with oat. In sludge cultivated with radish the 48 h EC₅₀ was 1700 mg Cu kg^-1 dry wt and 22 mg Sb kg^-1 dry wt. The effect of Cu could be predicted by pH and Cu concentrationin the elutriate, but the effect of Sb could not solely be explained by its concentration in the elutriate.     

Efficacy of Fe(o,o-EDDHA) and Fe(o,p-EDDHA) isomers in supplying Fe to strategy I plants differs in nutrient solution and calcareous soil

The FeEDDHA [iron(3+) ethylenediamine di(o-hydroxyphenylacetic) acid] is one of the most efficient iron chelates employed in the correction of iron clorosis in calcareous soils. FeEDDHA presents different positional isomers: the ortho-ortho (o,o), the ortho-para (o,p), and the para-para (p,p). Of these isomers, the p,p cannot chelate Fe in soil solution in a wide range of pH values, while both o,o and o,p can. The objective of this work was to compare the efficiency of both isomers (o,o and o,p) to provide Fe to two Strategy I plants (tomato and peach) in nutrient solution (pH approximately 6.0), as well as in calcareous soil (pH approximately 8.4; CALCIXEREPT). For this, chelates of both o,o-EDDHA and o,p-EDDHA with 57Fe (a nonradioactive isotope of Fe) were used, where the 57Fe acts as a tracer. The results obtained showed that the o,o isomer is capable of providing sufficient Fe to plants in both nutrient solution and calcareous soil. However, the o,p isomer is capable of providing sufficient Fe to plants in nutrient solution but not in calcareous soil.     

Acute Copper Toxicity and Acclimation to Copper Using the Behavioral Endpoint of Shoaling,in the Least Killifish (Heterandria formosa)

Water, Air, &; Soil Pollution - The release of heavy oil from laboratory-contaminated sediments was studied in a series of kinetic and equilibrium experiments. The kinetic curves could be...