Influence of the excystment time on the breeding success of juvenile freshwater pearl mussels (Margaritifera margaritifera)          下载免费PDF全文

Tanja Eybe  Frankie Thielen  Torsten Bohn  Bernd Sures 《水产资源保护:海洋与淡水生态系统》2015,25(1):21-30

Diversity studies in genetic resources of <Emphasis Type="Italic">Solanum</Emphasis> spp. (section Petota) by comparative application of ISAP markers     

Kerstin Diekmann  Kathrin M. Seibt  Katja Muders  Torsten Wenke  Holger Junghans  Thomas Schmidt  Klaus J. Dehmer 《Genetic Resources and Crop Evolution》2017,64(8):1937-1953

The Genebank at the Leibniz Institute of Plant Genetics and Crop Plant Research (IPK) harbours three different potato collections comprising 2846 wild potato accessions, 2757 accessions of cultivars, landraces and breeding material of Solanum tuberosum L. and 579 Solanum clones originating mainly from South and Central America (as of July 2016). The three collections are maintained via seeds, in vitro culture, cryopreservation or in the field. All four processes are labour and cost intensive. Therefore, methods facilitating the efficient management and maintenance of the collections are needed. We describe the experimental application of the retrotransposon-based Inter-SINE amplified polymorphism (ISAP) marker system for supporting the management of potato collections. Three ISAP primer combinations were evaluated on a set of 259 cultivated and 89 wild potato accessions focussing on three different aspects: diversity analysis, duplicate identification and phylogenetic studies. Compared to up to 29 microsatellites, ISAPs were similarly efficient in monitoring genetic diversity and detecting duplicated accessions. In addition, the three ISAP primer combinations could be applied to wild potato species, although their use in phylogenetic studies is limited due to their highly polymorphic nature. Generally, ISAPs are a very valuable tool in the maintenance of clonally maintained potato collections and for the verification of the identity of accessions.  相似文献   

A practical way to integrate risk in forest management decisions     

Torsten B. Möllmann  Bernhard Möhring 《Annals of Forest Science》2017,74(4):75

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Soil‐microbial response to sugarcane filter cake and biogenic waste compost     

Ghulam Rasul  Khalid S. Khan  Torsten Müller  Rainer Georg Joergensen 《植物养料与土壤学杂志》2008,171(3):355-360

An incubation experiment was carried out to examine the N‐immobilizing effect of sugarcane filter cake (C : N = 12.4) and to prove whether mixing it with compost (C : N = 10.5) has any synergistic effects on C and N mineralization after incorporation into the soil. Approximately 19% of the compost‐C added and 37% of the filter cake–C were evolved as CO₂, assuming that the amendments had no effects on the decomposition of soil organic C. However, only 28% of the added filter cake was lost according to the total‐C and δ¹³C values. Filter cake and compost contained initially significant concentrations of inorganic N, which was nearly completely immobilized between day 7 and 14 of the incubation in most cases. After day 14, N remineralization occurred at an average rate of 0.73 µg N (g soil)^–1 d^–1 in most amendment treatments, paralleling the N mineralization rate of the nonamended control without significant difference. No significant net N mineralization from the amendment N occurred in any of the amendment treatments in comparison to the control. The addition of compost and filter cake resulted in a linear increase in microbial biomass C with increasing amounts of C added. This increase was not affected by differences in substrate quality, especially the three times larger content of K₂SO₄‐extractable organic C in the sugarcane filter cake. In most amendment treatments, microbial biomass C and biomass N increased until the end of the incubation. No synergistic effects could be observed in the mixture treatments of compost and sugarcane filter cake.  相似文献   

Determination of water-extractable nonstructural carbohydrates, including inulin, in grass samples with high-performance anion exchange chromatography and pulsed amperometric detection     

Raessler M  Wissuwa B  Breul A  Unger W  Grimm T 《Journal of agricultural and food chemistry》2008,56(17):7649-7654

The exact and reliable determination of carbohydrates in plant samples of different origin is of great importance with respect to plant physiology. Additionally, the identification and quantification of carbohydrates are necessary for the evaluation of the impact of these compounds on the biogeochemistry of carbon. To attain this goal, it is necessary to analyze a great number of samples with both high sensitivity and selectivity within a limited time frame. This paper presents a rugged and easy method that allows the isocratic chromatographic determination of 12 carbohydrates and sugar alcohols from one sample within 30 min. The method was successfully applied to a variety of plant materials with particular emphasis on perennial ryegrass samples of the species Lolium perenne. The method was easily extended to the analysis of the polysaccharide inulin after its acidic hydrolysis into the corresponding monomers without the need for substantial change of chromatographic conditions or even the use of enzymes. It therefore offers a fundamental advantage for the analysis of the complex mixture of nonstructural carbohydrates often found in plant samples.  相似文献   

Nitrous oxide emissions after incorporation of winter oilseed rape (Brassica napus L.) residues under two different tillage treatments     

Katharina Kesenheimer  Hemant Raj Pandeya  Torsten Müller  Franz Buegger  Reiner Ruser 《植物养料与土壤学杂志》2019,182(1):48-59

The aim of this study was to investigate the effect of crop residues from winter oilseed rape on N₂O emissions from a loamy soil and to determine the effect of different tillage practices on N₂O fluxes. We therefore conducted a field experiment in which crop residues of winter oilseed rape (Brassica napus L., OSR) were replaced with ¹⁵N labelled OSR residues. Nitrous oxide (N₂O) emissions and ¹⁵N abundance in the N₂O were determined for a period of 11 months after harvest of OSR and in the succeeding crop winter wheat (Triticum aestivum L.) cultivated on a Haplic Luvisol in South Germany. Measurements were carried out with the closed chamber method in a treatment with conventional tillage (CT) and in a treatment with reduced soil tillage (RT). In both tillage treatments we also determined N₂O fluxes in control plots where we completely removed the crop residues. High N₂O fluxes occurred in a short period just after OSR residue replacement in fall and after N‐fertilization to winter wheat in the following spring. Although N₂O emissions differed for distinct treatments and sub‐periods, cumulative N₂O emissions over the whole investigation period (299 days) ranged between 1.7 kg and 2.4 kg N₂O‐N ha^?1 with no significant treatment effects. More than half of the cumulative emissions occurred during the first eight weeks after OSR replacement, highlighting the importance of this post‐harvest period for annual N₂O budgets of OSR. The contribution of residue N to the N₂O emission was low and explained by the high C/N‐ratio fostering immobilization of mineral N. In total only 0.03% of the N₂O‐N emitted in the conventional tillage treatment and 0.06% in the reduced tillage treatment stemmed directly from the crop residues. The ¹⁵N recovery in the treatments with crop residues was 62.8% (CT) and 75.1% (RT) with more than 97% of the recovered ¹⁵N in the top soil. Despite our measurements did not cover an entire year, the low contribution of the OSR residues to the direct N₂O emissions shows, that the current IPCC tier 1 approach, which assumes an EF of 1%, strongly overestimated direct emissions from OSR crop residues. Furthermore, we could not observe any relationship between tillage and crop residues on N₂O emission, only during the winter period were N₂O emissions from reduced tillage significantly higher compared to conventional tillage. Annual N₂O emission from RT and CT did not differ.  相似文献   

Strategic planning for new woodlands in the urban periphery: through the lens of social inclusiveness     

Ann Van Herzele  Eva M. De Clercq  Torsten Wiedemann 《Urban Forestry & Urban Greening》2005,3(3-4):177-188

Current strategies for creating new woodlands in the urban periphery aim to provide as many people as possible with a recreational green space close to where they live. When taking a socially inclusive approach, however, this also involves a number of ‘distributional’ questions. These refer to the kind of people likely to benefit the most from such a plan: urban or suburban residents, low or high-income groups, and so forth. This article presents a GIS-based working method aimed at exploring different options for urban woodland proposals with regard to their positioning in relation to residential areas, as well as the socio-spatial characteristics of those areas. The example of seven possible locations for a new ‘peri-urban forest’ in Antwerp, Belgium was used to demonstrate the method's potential to address relevant questions in socially inclusive planning and hence, to improve strategic planning for new urban woodlands.  相似文献   

Necrotizing encephalitis of unknown cause in Fennoscandian Arctic foxes (Alopex lagopus).     

Anna-Lena Berg  Dolores Gavier-Widén  Kristina Nilsson  Frederik Widén  Mikael Berg  Sune Gregorius  Erik Agren  Maria Erlandsson  Torsten M?rner 《Journal of veterinary diagnostic investigation》2007,19(1):113-117

A neurologic disease affected a colony of endangered Fennoscandian arctic foxes (Alopex lagopus) kept in captivity for breeding purposes. Several outbreaks of disease occurred between 1994 and 2004. The clinical signs included ataxia, indications of anosmia, blindness, and abnormal behavior. The disease was characterized by severe necrotizing encephalitis affecting mostly the cranial cerebrum, basal ganglia, and olfactory bulbs. Investigations to identify the etiology of the disease included testing for several infectious agents known to cause encephalitis in carnivores. Tests for Toxoplasma gondii, Encephalitozoon cuniculi, Neospora caninum, canine distemper virus, rabies, adenovirus type 1, Borna disease virus, and Listeria monocytogenes were negative. The colony was closed, and the cause of the disease remains undetermined.  相似文献   

Habitat factors for land snails in European beech forests with a special focus on coarse woody debris     

J?rg?MüllerEmail author  Christian?Str?tz  Torsten?Hothorn 《European Journal of Forest Research》2005,124(3):233-242

Analyses of land snails and habitat factors in acid beech forests were conducted in southern Germany (northern Bavaria). The objectives were to study the effects of habitat characteristics on snail density and species richness. Habitat structures were determined for 37 plots in one big forest. We found a significant relationship between the number of snail species and individuals and the following set of habitat factors coverage of herbaceous layer, growing stock, mean diameter at breast height of the three largest trees (DBHmax), stand age, total dead wood volume per ha, and advanced decomposed dead wood volume per ha. We use maximally selected rank statistics to estimate cutpoints separating stands with low densities, from stands with high snail densities. Here, we define cutpoints for a significant higher snail density at a stand age of 187 years, 57 m³/ha dead wood, 40 m³/ha advanced decomposed dead wood, 63 cm DBHmax and more than 1% herbaceous layer. For species richness, cutpoints are estimated at 338 m³/ha stand volume, 170 years stand age, 50 m³/ha total dead wood amount, 15 m³/ha advanced decomposed dead wood and 56 cm DBHmax. The microhabitat analysis shows a higher pH value and a higher Calcium content at the bottom of large snags and under large lying dead wood pieces in comparison to litter, upper mineral soil and at the bottom of vital living trees. Snail species and individual density are significantly linked to these patterns of chemical parameters. The identified cutpoints are a good base for ecological management decisions in forest management.  相似文献   

An improved low-input method for establishing calliandra hedgerows on small-scale farms in western Kenya     

Torsten Mandal  Niels Erik Nielsen 《Agroforestry Systems》2004,60(3):227-231

Direct seeding methods for nitrogen (N)-fixing tree-legumes by small-scale farmers were developed and studied in humid and sub-humid areas of western Kenya. We focused on the first six months of establishment of calliandra (Calliandra calothyrsus Meissner) multipurpose hedgerows. Direct seeding became effective, reliable, and significantly better than for zero-control treatments when improving A) water uptake by scratching the hard seeds with a sandal against a hard, rough surface, B) phosphorus (P) nutrition by mixing 150 g/m of kitchen wood-ash (1.3% P) into a 10 cm deep, 20 wide cm soil band 5 cm below the seeds, and C) root nodulation by transferring 100 g/m Rhizobium-colonised soil, or 0.5 crushed, incubated nodule, from a calliandra hedge. The field germination was 90% after two weeks, and the hedges were green and about 2 m tall in the dry season six months later. This revised version was published online in June 2006 with corrections to the Cover Date.  相似文献