No evidence of superclones in leaf-feeding forms of austrian grape phylloxera (Daktulosphaira vitifoliae)     

Forneck  Astrid  Anhalt  Ulrike C. M.  Mammerler  Roswitha  Griesser  Michaela 《European journal of plant pathology / European Foundation for Plant Pathology》2015,142(3):441-448

European Journal of Plant Pathology - The genetic structure of ten grape phylloxera populations, sampled in summer of 2006 and 2007 from four distinct viticultural areas in Austria, Daktulosphaira...  相似文献   

Elevated CO₂ stimulates N₂O emissions in permanent grassland   总被引：1，自引：1，他引：0  

Claudia Kammann  Christoph Müller  Ludger Grünhage  Hans-Jürgen Jger 《Soil biology & biochemistry》2008,40(9):2194-2205

To evaluate climate forcing under increasing atmospheric CO₂ concentrations, feedback effects on greenhouse gases such as nitrous oxide (N₂O) with a high global warming potential should be taken into account. This requires long-term N₂O flux measurements because responses to elevated CO₂ may vary throughout annual courses. Here, we present an almost 9 year long continuous N₂O flux data set from a free air carbon dioxide enrichment (FACE) study on an old, N-limited temperate grassland. Prior to the FACE start, N₂O emissions were not different between plots that were later under ambient (A) and elevated (E) CO₂ treatments, respectively. However, over the entire experimental period (May 1998–December 2006), N₂O emissions more than doubled under elevated CO₂ (0.90 vs. 2.07 kg N₂O-N ha⁻¹ y⁻¹ under A and E, respectively). The strongest stimulation occurred during vegetative growth periods in the summer when soil mineral N concentrations were low. This was surprising because based on literature we had expected the highest stimulation of N₂O emissions due to elevated CO₂ when mineral N concentrations were above background values (e.g. shortly after N application in spring). N₂O emissions under elevated CO₂ were moderately stimulated during late autumn–winter, including freeze–thaw cycles which occurred in the 8th winter of the experiment. Averaged over the entire experiment, the additional N₂O emissions caused by elevated CO₂ equaled 4738 kg CO₂-equivalents ha⁻¹, corresponding to more than half a ton (546 kg) of CO₂ ha⁻¹ which has to be sequestered annually to balance the CO₂-induced N₂O emissions. Without a concomitant increase in C sequestration under rising atmospheric CO₂ concentrations, temperate grasslands may be converted into greenhouse gas sources by a positive feedback on N₂O emissions. Our results underline the need to include continuous N₂O flux measurements in ecosystem-scale CO₂ enrichment experiments.  相似文献   

Monitoring of root‐zone water content in the laboratory by 2D geoelectrical tomography     

Ulrike Werban  Said Attia al Hagrey  Wolfgang Rabbel 《植物养料与土壤学杂志》2008,171(6):927-935

Root water uptake is one of the essential processes within the soil–plant–atmosphere continuum. We present a method for monitoring soil‐water redistributions due to water uptake by roots. Our aim is to image and monitor diurnal soil‐water redistribution during a small‐scale (centimeter‐to‐decimeter range) indoor experiment and to correlate water content determined by applied geoelectrical time‐lapse imaging techniques with values from single‐point time domain reflectometry (TDR) measurements. This includes establishing pedophysical relationships within the root zone and deriving the water‐content distribution from the electrical‐resistivity model. Using DC geoelectrics of high resolution (970 data points for 220 cm²), we monitored significant spatial heterogeneity of soil moisture with time, whereas no irrigation was applied. Thus, we imaged the high heterogeneity of fluid movements within the soil. We found diurnal variations with high spatial variability of soil water content during the morning and afternoon hours. The water content continuously increased from dawn to noon, whereas the increase started in the near‐surface zone from 1 cm to 3 cm above the main root zone. Between 8:00 a.m. and 10:00 a.m., water content decreases along most of the sections. Water content irregularly decreases and increases during the afternoon. During night time, we observed nearly no changes in soil water content due to the absence of transpiration and subsequently soil‐water redistribution. Most of these diurnal variations in soil water content lie within the intensive root zone, as measurements showed on soil samples excavated from these areas after the experiment. Furthermore, we quantified water content derived from geoelectrical tomography of the monitored area before and after an irrigation event using a geophysical pedotransfer function of Archie, established specifically for the used lupine and the applied physico‐chemical boundary conditions of the experiment. The resulting average water content from 2D geoelectrical tomography agreed well with the values determined by the TDR measurements.  相似文献   

Red fluorescence in reef fish: A novel signalling mechanism?     

Nico K Michiels  Nils Anthes  Nathan S Hart  Jürgen Herler  Alfred J Meixner  Frank Schleifenbaum  Gregor Schulte  Ulrike E Siebeck  Dennis Sprenger  Matthias F Wucherer 《BMC ecology》2008,8(1):16

Background  

At depths below 10 m, reefs are dominated by blue-green light because seawater selectively absorbs the longer, 'red' wavelengths beyond 600 nm from the downwelling sunlight. Consequently, the visual pigments of many reef fish are matched to shorter wavelengths, which are transmitted better by water. Combining the typically poor long-wavelength sensitivity of fish eyes with the presumed lack of ambient red light, red light is currently considered irrelevant for reef fish. However, previous studies ignore the fact that several marine organisms, including deep sea fish, produce their own red luminescence and are capable of seeing it.  相似文献   

Fish Biomechanics. Volume 23 in the Series 'Fish Physiology'     

Ulrike Müller 《Fish and Fisheries》2007,8(1):73-74

  相似文献   

An integrative approach for analysing landscape dynamics in diverse cultivated and natural mountain areas   总被引：3，自引：1，他引：2  

Erich Tasser  Flavio V. Ruffini  Ulrike Tappeiner 《Landscape Ecology》2009,24(5):611-628

Our landscape can be regarded as a development process that is affected and subsequently shaped by a series of different environmental and human-induced factors. However, to date, concrete data about the impact of each of these factors are still missing. One key reason for this is that methods of acquisition and evaluation of these factors inherently have differences, thereby preventing meaningful comparative analyses. This study presents an integrative methodical approach that bridges many of these gaps. Our approach also has the advantages of being generally applicable while delivering easily interpretable results that also allow comparisons between diverse geographical regions. The indicators used enable all major features of landscape change, e.g. changes in land use, landscape structuring, habitat settings, and urban sprawl, to be accurately monitored and provide high-quality realistic results that were validated in our study site, South Tyrol (North Italy). Indicators were selected for both their further subdivision, e.g. monocrops and different features of mixed crops, and their easy to ascertain hierarchically structured feature classification, e.g. land cover. Furthermore, our use of ecoregions enables better comparison of aspects of landscape development for geographical regions having diverse socio-economic and ecological conditions. Our methodical approach can be used as a basis not only for creating landscape change scenarios, but also for determining the environmental and human-induced factors involved and being able to list them in order of importance. Further the detected striking difference between the mapped land-use data and the official census data suggests a validation of the methodical approach in context of the national agriculture census.  相似文献   

Bodenmykoflora in unterschiedlichen Bewirtschaftungssystemen des Weizens mit besonderer Berücksichtigung der Fusarium‐Akten     

Ulrike Damm 《Archives of Agronomy and Soil Science》2013,59(6):509-521

In einem Feldversuch wurden in drei Jahren die Auswirkungen unterschiedlicher Bewirtschaftungssysteme des Weizens auf die Bodenmykoflora untersucht. Dabei wurde ein Bewirtschaftungssystem mit Vorfrucht Grünbrache, konservierender Bodenbearbeitung mit Grubber und unterlassener Stickstoffdüngung (Variante E) einem System mit Vorfrucht Silomais, konventioneller Bodenbearbeitung mit Pflug und mineralischer Stickstoffdüngung (Variante I) gegenübergestellt. Die Besiedlungsdichte und das Spektrum der Bodenpilze wurden durch Auslegen von Bodenpartikeln auf Nährboden untersucht. Die Artbestimmung der Gattung Fusarium stand dabei im Vordergrund.

Die Bodenproben der Variante E zeigten quantitativ und qualitativ eine höhere Pilzbesiedlung als die Proben der Variante I. Die Gattung Fusarium war zu jedem Probenahmetermin im Boden der Variante E deutlich häufiger, wobei sowohl saprophytische Arten (z. B. F. tabacinum) als auch die pathogene Art F. eulmorum zu nennen sind. Neben Fusarium zeigten auch Gattungen wie Alternaria, Cladosporium und Mucor die zum Teil antagonistische Fähigkeiten gegenüber F. eulmorum besitzen, höhere Abundanzen in den Bodenproben der Variante E.  相似文献   

Prevalence and antimicrobial susceptibility of Salmonella spp. in small Indian mongooses (Herpestes auropunctatus) in Grenada,West Indies     

Steven Miller  Victor Amadi  Diana Stone  Roger Johnson  Harry Hariharan  Ulrike Zieger 《Comparative immunology, microbiology and infectious diseases》2014

Intestinal samples from 156 small Indian mongooses (Herpestes auropunctatus) collected island-wide in Grenada from April 2011 to March 2013 were examined for the presence of Salmonella enterica spp. Nineteen (12%) mongooses were culture-positive for S. enterica spp. of which five serotypes were identified. Salmonella javiana and S. Montevideo were the most commonly isolated serotypes. The other serotypes isolated were S. Rubislaw, S. Panama and S. Arechavaleta. All isolates were susceptible to amoxicillin–clavulanic acid, ampicillin, cefotaxime, ceftazidime, ciprofloxacin, enrofloxacin, gentamicin, nalidixic acid, imipenem and trimethoprim–sulfamethoxazole. One isolate (S. Montevideo) showed resistance to tetracycline and intermediate resistance to streptomycin. The five isolated Salmonella serotypes are potential human pathogens suggesting that the mongoose may play a role in the epidemiology of human salmonellosis in Grenada.  相似文献   

A combined hydraulic and toxicological approach to assess re-suspended sediments during simulated flood events. Part I–multiple biomarkers in rainbow trout     

Markus Brinkmann  Sebastian Hudjetz  Catrina Cofalla  Sebastian Roger  Ulrike Kammann  John P. Giesy  Markus Hecker  Steve Wiseman  Xiaowei Zhang  Jan Wölz  Holger Schüttrumpf  Henner Hollert 《Journal of Soils and Sediments》2010,10(7):1347-1361

Purpose

One of the central issues related to global changes in weather is the increasing occurrence of flood events that can result in the re-suspension of contaminated sediments in rivers. Here, we report on a proof-of-concept study combining hydraulic engineering and ecotoxicology in a new interdisciplinary approach to assess the toxicity of re-suspended polluted sediments after a simulated flood event.

Materials and methods

Rainbow trout (Oncorhynchus mykiss) were exposed for 5 days under simulated flood conditions in an annular flume with artificial sediments that were spiked with a mixture of polycyclic aromatic hydrocarbons (PAH) at environmentally relevant concentrations. Specifically, the objective of this study was to bridge the gap between the physical re-suspension of pollutants and resulting toxicological impacts on aquatic organisms. A suite of different molecular, biochemical and histological markers was used to test the hypothesis that re-suspension of sediments can lead to re-mobilization of PAHs and subsequently to effects on aquatic organisms.

Results and discussion

The micronucleus frequency was significantly 4.3-fold elevated after exposure. There was no significant indication of Aryl hydrocarbon receptor signaling (no EROD induction or increased CYP1A protein content, only slight induction of CYP1A gene expression). Biliary metabolite concentration was the most sensitive marker of PAH exposure. Results for other biomarkers (glutathione-S-transferase, catalase and lipid peroxidation) were inconclusive.

Conclusions

In combination with chemical analyses of suspended matter, the presented approach will be used to improve understanding of the re-mobilization of pollutants from sediments in support of environmental risk assessment.  相似文献   

Comparison of the effect of hypertonic hydroxyethyl starch and mannitol on the intraocular pressure in healthy normotensive dogs and the effect of hypertonic hydroxyethyl starch on the intraocular pressure in dogs with primary glaucoma     

Volopich S  Mosing M  Auer U  Nell B 《Veterinary ophthalmology》2006,9(4):239-244

PURPOSE: The purpose of this study was to determine if intravenous hypertonic hydroxyethyl starch (7.5%/6%) (HES) could decrease the intraocular pressure (IOP) in healthy normotensive dogs, and compare its effect with that of mannitol (20%) (experimental study). In addition, the potential IOP-lowering effect of hypertonic HES was evaluated in six dogs with primary glaucoma (clinical study). MATERIAL AND METHODS: Experimental study: eight male ophthalmoscopically and clinically healthy Beagles were included in this study. The IOP of each dog was measured by applanation tonometry in both eyes to obtain control values at 10:00, 10:15, 10:30, 10:45, 11:00 a.m., and then every hour until 6:00 p.m. prior to the first treatment (control period). Each dog received, with at least 2-week intervals and in a random order, an intravenous (IV) infusion of 4 mL/kg hypertonic HES (1.2 g/kg NaCl; 0.96 g/kg HES) and 4 mL/kg mannitol 20% (1 g/kg) over a period of 15 min starting at 10:00 a.m. IOP was measured oculus uterque (OU) at the same time intervals as in the control study. The differences in IOP between the treatment groups and the baseline IOP (before the start of infusion), between oculus sinister (OS) and oculus dexter (OD) and between the same time points of all groups were determined with a Student's t-test for paired samples (P = 0.05). Clinical study: six dogs with primary glaucoma (representing seven eyes) received an IV infusion of 4 mL/kg hypertonic HES over a period of 15 min. IOP was measured before and 15 and 30 min after starting the infusion. RESULTS: Experimental study: no significant difference between IOP of both eyes was found. A significant decrease in IOP from baseline value was recorded at 15, 30, 45, and 60 min after the start of mannitol infusion (mean amplitude in IOP decrease 3.21 mmHg; P < 0.05) and at 15 and 30 min in dogs treated with HES (mean amplitude in IOP decrease 2.43 mmHg; P < 0.05). At 120 and 180 min there was a significantly higher IOP (P < 0.05) in HES treatment group compared to the values of the control group. Clinical study: in 5/7 eyes diagnosed with primary glaucoma a maximum decrease in IOP of an average of 24% from the baseline value (IOP before start of the infusion) was observed (range of decrease 2-21 mmHg). In three of these five cases the maximum decrease was reached at 15 min and in two cases at 30 min. In one case an increase in IOP of 35% (+ 18 mmHg) was seen after 15 min and 26% (+ 13 mmHg) after 30 min. Case 4 showed an increase in IOP of 5% (+ 3 mmHg) after 15 min and a decrease of 6% (- 4 mmHg) after 30 min. CONCLUSIONS: Intravenous hypertonic HES is comparable to intravenous mannitol 20% in lowering the intraocular pressure in healthy normotensive dogs. But this effect lasted half an hour longer after mannitol. In 6/7 eyes with primary glaucoma, hypertonic HES decreased IOP.  相似文献