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1.
T. W. Eschholz P. Stamp R. Peter J. Leipner A. Hund 《Genetic Resources and Crop Evolution》2010,57(1):71-84
Between 1930 and 2003 with emphasis on the 1940s maize landraces (Zea mays L. ssp. mays) from all over Switzerland were collected for maintenance and further use in a new Swiss breeding program. The genetic relationship
and diversity among these accessions stored in the Swiss gene bank is largely unknown. Our hypothesis was that due to the
unique geographic, climatic, and cultural diversity in Switzerland a diverse population of maize landraces had developed over
the past three centuries. The aims were to characterize the genetic diversity of the Swiss landraces and their genetic relationship
with accessions from neighbouring regions as well as reviewing their history, collection, and maintenance. The characterization
and grouping was based on analyses with ten microsatellite markers. Geographic, cultural, and climatic conditions explained
a division in two distinct groups of accessions. One group consisted of landraces collected in the southern parts of Switzerland.
This group was related to the Italian Orange Flints. The other group contained accessions from northern Switzerland which
were related to Northern European Flints in particular German Flints. Historic evidence was found for a frequent exchange
of landraces within the country resulting in a lack of region-specific or landrace-specific genetic groups. The relatively
large separation between the accessions, indicated by high F
ST (0.42), might be explained partly by a bottleneck during the collection and maintenance phase as well as by geographical
and cultural separation of north and south of the country. Due to the high genetic diversity, the accessions here are a potential
resource for broadening the European flint pool. 相似文献
2.
Mohammad Abu Shayed Heike Hund Rolf Dieter Hund Chokri Cherif 《Fibers and Polymers》2016,17(2):229-240
Thermal and oxidation resistant coating is necessary for carbon fiber (CF) in CF reinforced concrete (CFRC) composite application in order to fulfil a high level of safety standard in case of fire. Pre-ceramic coatings such as Polysilazane, Polysiloxane, and Methyl silicone resin have been deposited on CF filament yarn by means of wet chemical continuous dip coating method. The surface analyses e.g. scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS) and infrared spectroscopy (IR) results showed the changes of surface morphology by the coatings. Thermo gravimetric analysis (TGA) revealed that the high temperature (up to 800 °C) oxidation stability of CF was significantly improved with coatings. Thermo-mechanical properties also significantly enhanced up to 600 °C. CF yarn retains its original strength and elasticity modulus/stiffness at 700 °C due to thermal and oxidation resistant coatings. 相似文献
3.
Ultrahigh molecular weight polyethylene (UHMW PE) has high chemical resistance, good flexibility and remarkable strength along with low density, which makes it a good choice for lightweight textile reinforced composites. One drawback is the low melting point, limiting the possible applications at high temperatures. However its chemical structure leads to almost no chemical interactions of the interface. One way to enhance these interactions is the application of atmospheric pressure plasma. Polyethylene (PE) as yarn and in woven form was plasma treated in atmospheric air plasma generated by means of dielectric barrier discharge technique and the resulting effects on wettability, chemical composition and surface structure were studied. It was found that oxygen containing functional groups are introduced into the outer layer of the PE, thus increasing wettability and dyeability significantly. It could be shown that the changes last for at least 3 months in air without the necessity of any precautions. A degradation of the textile fibre during air plasma treatment was also observed, leading to a decrease of tensile strength and maximum elongation after more than five minutes of air plasma treatment. 相似文献
4.
Inert polyethylene terephthalate (PET) yarns, which were spooled crosswise onto a cylindrical dyeing bobbin, were silvered successfully with a wet-chemical method by using a newly developed one-bath method on a laboratory scale. In order to characterize the silver coating such as design, homogeneity, and crack formation, the surface morphology (SM) was analyzed using scanning electron microscopy (SEM). The chemical compositions of the surface (percentage of carbon, oxygen, nitrogen, silicium, and silver) were investigated with energy-dispersive x-ray spectroscopy (EDX). Furthermore, the testing of textile-chemical and textile-physical properties such as the washing-fastness, tensile strength, and electrical conductivity was carried out. 相似文献
5.
Heat resistant coatings of textile materials are required so that they can fulfill the high security demand in the case of resistance to fire and improve thermo-mechanical properties. These coatings also enhance the interface properties of textiles in the composites. Liquid phase coatings, based on polysilazane and polysiloxane polymers were deposited onto the basalt fiber (BF) yarn using impregnation coating method. Tensile testing under thermal stress was conducted to examine the thermo-mechanical properties of both coated and uncoated yarns. The thermo-mechanical study indicated that the heat resistant coatings enhanced 40–70 % tensile strength and 25–40 % stiffness of original BF yarns up to 400 °C. BF yarn retained 65–90 % of its tensile strength at 500 °C due to coatings, whereas the uncoated BF yarn lost 85 % strength at this temperature. Thermo gravimetric analysis (TGA) showed that the coatings have good thermal stability. In addition, scanning electron microscopy (SEM), energy-dispersive X-ray (EDX) spectroscopy, optical microscopy and fourier transform infrared (FTIR) spectroscopy analyses were executed in order to evaluate the surface microstructure as well as surface chemical compositions of the BF yarns. 相似文献
6.
Differential determination of fungal- and bacterial bioactivity in two spruce forest ecosystems To determine the general bioactivity and the contribution of actinomycetes and fungi in organic and mineral horizons of two spruce forests (Luvic Cambisol and Dystric Podzoluvisol) different physiological methods were utilized and compared. According to microbial measurements (ATP-quantity, heat output) the activity in Ebersberger Forst surpassed that of Höglwald in each horizon. The measurements of ergosterol and chitin delivered contradictory results. A similarity between the amount of glucosamine and that of fluorescein diacetate hydrolysis was observed. In the activity of lignin degrading fungi and ethylene production both soils differed entirely. 相似文献
7.
Stem elongation is a critical phase for yield formation in wheat (Triticum aestivum). This study proposes the use of terrestrial laser scanning (TLS) for phenotyping of growth dynamics during wheat stem elongation in high temporal resolution and high throughput in the field. TLS was implemented on a novel field phenotyping platform carrying a cable suspended sensor head moveable in 3D over a 1 ha field. Canopy height was recorded on 335 winter wheat genotypes across two consecutive years. Scans were done in 3-d intervals during the stem elongation phase. Per day, 714 plots (two replications plus checks) were scanned within 3.5 h. The results showed that canopy height increased linearly with thermal time. Based on this linearity, 15 and 95% of final height were used as proxy measures for the onset and termination of stem elongation, respectively. We observed high heritability between 0.76 and 0.91 for the onset, termination and duration of stem elongation. The onset of stem elongation showed a positive covariance with the termination of stem elongation and final height indicating some regulatory dependencies. Yet there was no apparent relationship between onset and duration of stem elongation. Due to its precision, the TLS method allows to measure the dynamics of stem elongation in large sets of genotypes. This in turn offers opportunities to investigate the genetic control of the transitions between early vegetative growth, stem elongation and flowering. Understanding the genetic control of these transitions is an important milestone towards knowledge-based crop improvement. 相似文献
8.
Hund A Gollnick N Sauter-Louis C Neubauer-Juric A Lahm H Büttner M 《Veterinary microbiology》2012,154(3-4):247-256
The compulsory vaccination campaign against Bluetongue virus serotype eight (BTV-8) in Germany was exercised in the state of Bavaria using three commercial monovalent inactivated vaccines given provisional marketing authorisation for emergency use. In eleven Bavarian farms representing a cross sectional area of the state the immune reactions of sheep and cattle were followed over a two year period (2008-2009) using cELISA, a serum neutralisation test (SNT) and interferon gamma (IFN-γ) ELISPOT. For molecular diagnostics of BTV genome presence two recommended real time quantitative RT-PCR protocols were applied. The recommended vaccination scheme led to low or even undetectable antibody titers (ELISA) in serum samples of both cattle and sheep. A fourfold increase of the vaccine dose in cattle, however, induced higher ELISA titers and virus neutralising antibodies. Accordingly, repeated vaccination in sheep caused an increase in ELISA-antibody titers. BTV-8 neutralising antibodies occurred in most animals only after multiple vaccinations in the second year of the campaign. The secretion of interferon gamma (IFN-γ) in ELISPOT after in vitro re-stimulation of PBMC of BTV-8 vaccinated animals with BTV was evaluated in the field for the first time. Sera of BTV-8 infected or vaccinated animals neutralising BTV-8 could also neutralise an Italian BTV serotype 1 cell culture adapted strain and PBMC of such animals secreted IFN-γ when stimulated with BTV-1. 相似文献
9.
Methods for relative quantifying fungi biomass in soils To estimate the mycological contribution in soil microflora, the amount of chitin and ergosterol and the decolorisation of Poly-B-411 dye was measured in three different soils. The tests showed a linear proportionality between the amount of soil and the respective quantities of the substances. Due to the methodic procedure, ergosterol was measured more accurately than chitin. The decolorisation of the Poly-B-411 dye was in wet humidic aerobic soil higher than in soil suspension. The stability of the adsorbance ratio (593/483 nm), which is a measure for the degradation, was obtained between the 5th and 7th day. 相似文献
10.
Tobias W. Eschholz Roland Peter Peter Stamp Andreas Hund 《Genetic Resources and Crop Evolution》2008,55(7):971-983
About 65 years ago, more than 150 Swiss maize landraces (Zea mays L. ssp. mays) of the flint type were collected and conserved ex situ. Due to the climatically and culturally diverse environment of the Alps, a considerable genetic diversity of this material
was assumed. To prove this, an efficient method was required to carry out genetic profiling of all the accessions in the Swiss
Gene Bank. Simple sequence repeat marker (SSR) profiling in combination with the visualization of the polymerase chain reaction
(PCR) products on agarose gels was chosen. Here a set of 19 different landrace accessions was analyzed to: (i) investigate
their genetic diversity, (ii) investigate and display the population structure and (iii) determine whether DNA bulks rather
than single plants can be used for such analyses. Four repeated samples of one accession were found to be much closer to one
another than to the rest of accessions. Furthermore, specific alleles were identified for several accessions. The PCR products
of the bulked DNA samples represented only a small part of the variation revealed by the analysis of individuals. Loci with
four base repeat motifs performed better in the analysis of bulks than loci with other repeat motifs. The correlation between
genetic distance matrices, based on the analysis of individuals and bulks, respectively, was significant. Thus, the single
plant approach allowed for sufficient differentiation of accessions, and DNA bulks visualized on agarose gels led to correlated
genetic distances although a limited number of alleles were detected. Although the limited resolution of agarose gels likely
causes some bias, profiling of larger sets with the individual plant approach appears feasible and more informative compared
to the bulk analysis we conducted. 相似文献