Staff Publications

Staff Publications

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    'Staff publications' is the digital repository of Wageningen University & Research

    'Staff publications' contains references to publications authored by Wageningen University staff from 1976 onward.

    Publications authored by the staff of the Research Institutes are available from 1995 onwards.

    Full text documents are added when available. The database is updated daily and currently holds about 240,000 items, of which 72,000 in open access.

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Changing regional weather-crop yield relationships across Europe between 1901 and 2012
Trnka, M. ; Olesen, J.E. ; Kersebaum, K.C. ; Rötter, R.P. ; Brázdil, R. ; Eitzinger, J. ; Janssen, Sander ; Skjelvåg, A.O. ; Peltonen-Sainio, P. ; Hlavinka, P. ; Balek, J. ; Eckersten, H. ; Gobin, A. ; Vučeti, V. ; Marta, A. Dalla; Orlandini, S. ; Alexandrov, V. ; Semerádová, D. ; Štěpánek, P. ; Svobodová, E. ; Rajdl, K. - \ 2016
Climate Research 70 (2016)2. - ISSN 0936-577X - p. 195 - 214.
Barley - Climatic trend - Drought - Europe - Weather-crop yield relationship - Wheat - Yield trend

Europe is, after Asia, the second largest producer of wheat in the world, and provides the largest share of barley. Wheat (and to a similar extent, barley) production in Europe increased by more than 6-fold during the 20th century. During the first half of the 20th century, this was driven by expanding the harvested area. This was followed, from the mid-20th century, by a massive increase in productivity that in many regions has stalled since 2000. However, it remains unclear what role climatic factors have played in these changes. Understanding the net impact of climatic trends over the past century would also aid in our understanding of the potential impact of future climate changes and in assessments of the potential for adaptation across Europe. In this study, we compiled information from several sources on winter wheat and spring barley yields and climatological data from 12 countries/regions covering the period from 1901-2012. The studied area includes the majority of climatic regions in which wheat and barley are grown (from central Italy to Finland). We hypothesized that changes in climatic conditions have led to measurable shifts in climate-yield relationships over the past 112 yr, and that presently grown wheat and barley show a more pronounced response to adverse weather conditions compared to crops from the early 20th century. The results confirm that climate-yield relationships have changed significantly over the period studied, and that in some regions, different predictors have had a greater effect on yields in recent times (between 1991 and 2012) than in previous decades. It is likely that changes in the climate-yield relationship at the local level might be more pronounced than those across the relatively large regions used in this study, as the latter represents aggregations of yields from various agroclimatic and pedoclimatic conditions that may show opposing trends.

Identification of oligoclonal agamospermous microspecies : Taxonomic specialists versus microsatellites
Kirschner, Jan ; Oplaat, Carla ; Verhoeven, Koen J.F. ; Zeisek, Vojtěch ; Uhleman, Ingo ; Trávníček, Bohumil ; Räsänen, Juhani ; Wilschut, Rutger A. ; Štěpánek, Jan - \ 2016
Preslia 88 (2016)1. - ISSN 0032-7786 - p. 1 - 17.
Agamospermy - Clonality - Microsatellite variation - Plant identification - Population variation - Taraxacum - Taxonomy

There has been a decrease in the ability of biologists to identify their material correctly, particularly plants of complicated genera with common agamospermy, where old clonal entities are accorded the rank of species (microspecies). Agamospermous microspecies are taxonomic entities recognizable from one another by a set of minute morphological features. The knowledge of microspecies is confined to a few specialists. Specialists use microspecies names but there could be inconsistencies in the taxonomic concepts used by different, geographically remote experts. A selection of nine widespread, generally recognized agamospermous microspecies of Taraxacum sect. Taraxacum, which are characterized by means of eight microsatellite loci, were used to evaluate the ability of four European Taraxacum specialists to identify these microspecies consistently. With two exceptions (and one unclear result) for 125 plants coming from an area extending from Finland to central Europe, the experts identified the microspecies consistently, exclusively on the basis of morphological differences. Another problem studied was within-species variation. The within-species microsatellite variation corresponded to the mutational clone cluster hypothesis, with a single unclear result. Each microspecies consisted of one, more or less dominant, clone and several minority clones, each usually confined to a single plant. A combination of the traditional microspecies identification by experts and the characterization of microspecies by a set of molecular markers opens the field of microtaxonomy to a wider group of researchers.

Multicompartment Nanoparticles Formed by a Heparin-Mimicking Block Terpolymer in Aqueous Solutions
Uchman, M. ; Stepanek, M. ; Prochazka, K. ; Mountrichas, G. ; Pispas, S. ; Voets, I.K. ; Walther, A. - \ 2009
Macromolecules 42 (2009)15. - ISSN 0024-9297 - p. 5605 - 5613.
atomic-force microscopy - abc triblock copolymer - onion-type micelles - fluorescence correlation spectroscopy - diblock copolymers - selective solvents - light-scattering - poly(2-vinylpyridine)-block-poly(ethylene oxide) - wormlike micelles - star terpolymers
A new amphiphilic block. terpolymer poly((sulfamate-carboxylate)isoprene)-block-polystyrene-block-poly(ethyl ene oxide), PISC230-PS52-PEO151, with a narrow molecular weight distribution (PDI = 1.05), was synthesized via the post. polymerization reaction of the anionically prepared precursor block terpolymer polyisoprene-block-polystyrene-block--poly(ethylene oxide) with chlorosulfonyl isocyanate. The formation and Structure of self-assemblies of the polyelectrolyte block terpolymer in dilute aqueous Solutions were studied by static and dynamic light scattering, atomic force and cryogenic transmission electron microscopy, fluorometry, and H-1 NMR spectroscopy. In acidic solutions, the terpolymers self-assemble into kinetically trapped multicompartment micelles, with the core consisting of discrete PS and PISC domains and PEO in the shell. If the solution pH is adjusted to the alkaline region, the multicompartment micelles undergo an irreversible transition to regular micelles, with a PS core and a mixed shell formed by PEO and PISC blocks.
Two new apomictic Taraxacum microspecies of the section Erythrosperma from central Europe
Vasut, R. ; Stepanek, J. ; Kirschner, J. - \ 2005
Preslia 77 (2005)2. - ISSN 0032-7786 - p. 197 - 210.
Two new species, Taraxacum maricum and Taraxacum cristatum, of the section Erythrosperma from Central Europe are described in this paper. These species are similar to western European taxa, T. maricum to T. proximum, and T. cristatum is morphologically close to T. scanicum. Both new taxa are triploid apomictic microspecies. Specific characteristics, information on distribution and ecology and comparison with similar species are presented. Pictures and distribution maps of the new species are also included.
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