Variation of Plant Electrophysiology in Cucumber under Different Water Status

AP and VP were measured in cucumbers under water sufficiency and water stress. The results indicated that, the AP would be evoked by electrical impulse, for water-stressed cucumber, its amplitude could reached more than 40 mV which was obviously greater than that (about 10-20mV) of plant under well-watered,and no VP came out. Along with the intensity of light increased, the VP appeared going-up trend, and accompanied by evidently spiking electrical signal, for plant under water stress, the VP increased more clearly, but the change of spiking amplitude of AP (about 3mV) was rather smaller than that (8-10mV) of plant under well-wa-tered.     

荷兰黄瓜收获机器人的研究开发

为了降低黄瓜人工收获费用，荷兰农业环境工程研究所已经成功开发出了移动式黄瓜收获机器人样机。重点研究了机器人视觉识别系统软件和机械手运动控制程序。移动式黄瓜收获机器人由4部分组成：行走车、机械手、视觉系统和末梢执行器。试验表明该机器人的行走车能够快速到达初步作业位置，视觉系统能够探测到黄瓜果实的精确位置及成熟度，末梢执行器可以抓取黄瓜果实并将果实从茎秆上分离。     

秸秆和地膜双元覆盖对设施黄瓜根系生长和根际土壤养分的影响

[目的]研究秸秆和地膜双元覆盖条件对设施黄瓜结果期根系生长和根际土壤养分含量的影响,为北方寒旱区设施农业可持续生产提供理论依据和技术支持。[方法]以设施黄瓜为试材,采用日光温室试验和室内测定的分析方法。[结果]玉米秸秆加地膜的双元覆盖处理可明显增加根际土壤有机质、氮、磷、钾等养分含量,促进植株根系生长,其中0.72kg/m2秸秆量并覆膜处理效果和推广性最佳,与对照相比,在结果后期提高根际土壤有机质、全磷、全钾、碱解氮含量及根系数、根冠比、总根长、根表面积、根系活力分别达20.83%,22.83%,5.16%,5.53%,73.24%,32.76%,65.42%,45.94%和10.41%。[结论]秸秆和地膜复合的双元覆盖效果优于秸秆或地膜单一覆盖处理。     

Bioassay-directed Fractionation of Organic Extracts of Marine Surface Sediments from the North and Baltic Sea - Part II: Results of the biotest battery and development of a biotest index (8 pp)

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Part I: Determination and identification of organic pollutants Part II: Results of the biotest battery and development of a biotest index

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Preamble. This series of two papers presents the results of an interdisciplinary research project (ISIS) dealing with bioassay-directed fractionation of marine sediment extracts. Part I presents the extraction and fractionation procedure as well as the results of chemical analysis, including non-target analysis of sediments. Part II describes the results of the biotest battery in relation to chemicals possibly causing parts of the observed effects. A biotest index is used to compare the toxicities of the samples.

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AUTHORS / AFFILIATIONS Ninja Reineke (3), Werner Wosniok (4), Dirk Danischewski (1), Heinrich Hühnerfuss (3), Angelika Kinder (5), Arne Sierts-Herrmann (5), Norbert Theobald (2), Hans-Heinrich Vahl (6), Michael Vobach (1), Johannes Westendorf (6) and Hans Steinhart (5).

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(1) Federal Research Centre for Fisheries, Institute for Fishery Ecology, Palmaille 9, 22767 Hamburg, Germany (2) Federal Maritime and Hydrographic Agency, Bernhard-Nochtstr. 78, 20359 Hamburg, Germany (3) University of Hamburg, Institute for Organic Chemistry, Martin-Luther-King-Platz 6, 20146 Hamburg, Germany (4) University of Bremen, Institute of Statistics, Bibliothekstr. 1, 28334 Bremen, Germany (5) University of Hamburg, Institute for Food Chemistry, Grindelallee 117, 20146 Hamburg, Germany (6) University of Hamburg, University Hospital Hamburg-Eppendorf, Department for Toxicology, Vogt-Kölln-Str. 30, 22527 Hamburg, Germany (7) Eurofins Wiertz-Eggert-Jörissen, Stenzelring 14b, 21107 Hamburg, Germany

Goal, Scope and Background

The ecological relevance of contaminants in mixtures is difficult to assess, because of possible interactions and due to lacking toxicity data for many substances present in environmental samples. Marine sediment extracts, which contain a mixture of environmental contaminants in low concentrations, were the object of this study. The extracts were investigated with a set of different biotests in order to identify the compound or the substance class responsible for the toxicity. For this goal, a combination of biotests, biotest-directed fractionation and chemical analysis has been applied. Further on, a strategy for the development of a biotest index to describe the toxicity of the fractions without a prior ranking of the test results is proposed. This article (Part II) focuses on the biological results of the approach.

Methods

The toxicological potential of organic extracts of sediments from the North Sea and the Baltic Sea was analyzed in a bioassay-directed fractionation procedure with a set of biotests: luciferase reporter gene assays on hormone receptor and Ah receptor, arabinose resistance test, fish embryo test (Danio rerio), comet assay, acetylcholinesterase inhibition test, heat-shock protein 70 induction, oxidative stress and luminescence inhibition test (Vibrio fischeri). The test results provided the basis for the calculation of a biotest index by factor analysis to compare the toxicity of the samples and fractions.

Results and Discussion

Results of 11 biotests on different fractionation levels of the samples were described and discussed with regard to the occurrence of contaminants and their toxic potentials. Polychlorinated biphenyls, polycyclic aromatic hydrocarbons, quinones, brominated indoles and brominated phenols were in the focus of interest. A biotest index was constructed to compare the toxic responses in the samples and to group the biotest results.

Conclusion

The procedure presented in this study is well suited for bioassay-directed fractionation of marine sediment extracts. However, in relatively low contaminated samples, high enrichment factors and sufficient fractionation is necessary to allow identification of low concentrations of contaminants which is required to link effects and possible causes. In the present case, the relation between substances and effects was difficult to uncover due to relatively low concentrations of pollutants compared to the biogenic matrix and to the remaining complexity of the fractions. The results, with respect to the brominated phenols and indoles in the samples, highlight the successful use of bioassay directed fractionation in the case of high concentrations and high toxicity.

Recommendation and Outlook

In general, it has been shown that a marine risk assessment requires focusing on the input of diffuse sources and taking into account the fact of mixture toxicity. Effects resulting from biogenic substances will make the assessment of the influence of anthropogenic substances even more difficult.     

CO2施肥对黄瓜幼苗矿质营养吸收与分配的影响

以土培和砂培黄瓜幼苗为试材，研究CO₂施肥对植株矿质营养吸收和分配的影响。结果表明：每天上午以1100±100 μl/L CO₂浓度施肥3 h或上、下午各施肥3 h明显降低植株各部位多数矿质元素的含量，CO₂施肥时间延长，降幅增大。CO₂施肥增强了黄瓜对矿质元素的吸收能力，使单株吸收总量显著增加，且施肥时间越长，吸收数量越多。因此，在CO₂施肥的同时应增加矿质营养的供给。     

CsFAD7基因转化烟草的研究

以"革新一号"烟草种子为试材,采用根癌农杆菌介导的烟草叶盘转化法将来源于黄瓜的脂肪酸去饱和酶基因(FAD7)转入烟草,并在附加300mg/L氨苄青霉素(Amp)的MS+0.1mg/L NAA+1.0mg/L 6-BA的培养基上诱导植株分化,再生芽在附加300mg/L Amp和100mg/L卡那霉素(Kan)的MS培养基上生根,获得再生植株。结果表明:Kan阳性植株经PCR检测筛选,得到转基因阳性植株,证明异源FAD基因已转入烟草基因组中。T1代经PCR-South-ern检测证明转化基因可以遗传;转基因烟草在低温胁迫下生长较好,叶绿素荧光参数F0值下降不大,Fv/Fm值保持较高,表现了对低温的耐受能力,脂肪酸分析表明,该基因可以使烟草叶片的亚麻酸含量比例升高。     

多效唑对大叶黄杨、金叶女贞、紫叶小檗的抗旱性影响研究

采取盆栽控水法,研究多效唑对大叶黄杨、金叶女贞、紫叶小檗等绿篱植物抗旱性影响,以期为节水管理提供依据。结果表明:在干旱条件下,3种绿篱植物应用适宜浓度的多效唑可不同程度的增强抗旱性。单就抗旱性而言,大叶黄杨的适宜浓度范围为1.33~9.33 g/L,最佳浓度为6.67 g/L;金叶女贞和紫叶小檗适宜浓度均为1.33~4.00 g/L,最佳浓度为2.67 g/L。     

3种污水对小麦和黄瓜幼苗生长发育的影响

通过水培试验,研究了天津市3个主要污水处理厂的进水在不同清污比例处理下对小麦和黄瓜幼苗发芽率、生物量、根质量和根长的影响。结果表明,与对照相比,3种污水对小麦和黄瓜的发芽率影响不大,但是对根长有明显的抑制作用,各个处理间根长差异显著(P0.05),小麦和黄瓜的根长抑制率变化范围分别为20%~64%和6%~48%。3种污水对黄瓜的生物量均表现为不同程度的促进作用,但Ⅲ号污水对小麦的生物量和根质量表现为抑制作用。根对污水中污染物响应最敏感,根据污水对根长的影响程度得出3个污水处理厂的进水对小麦和黄瓜的毒害作用依次为:Ⅲ号Ⅱ号Ⅰ号。     

NaCl胁迫对黄瓜幼苗生长及可溶性物质含量的影响

土壤盐渍化加重和淡水资源短缺,对黄瓜的产量、品质和风味影响很大。试验表明：NaCl胁迫可以明显提高幼苗叶片的相对电导率,降低叶片和根系的相对含水量,使黄瓜幼苗体内的有机渗透调节物质如脯氨酸、可溶性糖的含量增加;脯氨酸等含量的增加可以增强细胞的渗透调节能力,减少盐离子对细胞造成的伤害;无机渗透调节离子Na^＋在盐胁迫下含量增加,而K^＋的含量降低。     

多因子联合诱导系统的构建及对黄瓜白粉病防治试验

由多个不同的抗病诱导因子组成植物抗病诱导系统的1个子系统。每个因子都是这个系统中的1个要素。系统的性质不但取决于系统中的要素,还取决于要素的结构。合理的配伍可以使要素与要素之间、要素与系统之间的关系得以优化,使系统的功能得以强化。把筛选得到的多个不同的抗病诱导因子进行配伍,组合成新的"诱导组合体",其诱导效应比单一因子显著提高;用不同的"诱导组合体"进行"相继诱导"和"循环诱导",则进一步提高诱导效应,对黄瓜白粉病的田间防治效果达到78.16%,高于常规杀菌剂的防治效果。