Publications
NIBIOs employees contribute to several hundred scientific articles and research reports every year. You can browse or search in our collection which contains references and links to these publications as well as other research and dissemination activities. The collection is continously updated with new and historical material.
2014
Authors
Igor A. Yakovlev YeonKyeong Lee Björn Rotter Jorunn Elisabeth Olsen Tore Skrøppa Øystein Johnsen Carl Gunnar FossdalAbstract
Embryogenesis is the initial stage of plant life, when the basics of body plan and the post-embryonic development are laid down. Epigenetic memory formed in the Norway spruce embryos permanently affect the timing of bud burst and bud set in progenies, vitally important adaptive traits in this long-lived forest species. The epigenetic memory marks are established in response to the temperature conditions prevailing during zygotic and somatic embryogenesis; the epitype is fixed by the time the embryo is fully developed and is mitotically propagated throughout the tree’s life span. Somatic embryogenesis closely mimics the natural zygotic embryo formation and results in epigenetically different plants in a predictable temperature-dependent manner with respect to altered phenology. Using Illumina-based Massive Analysis of cDNA Ends, the transcriptome changes were monitored in somatic embryos during morphogenesis stage under two different temperatures (18 vs. 30 °C). We found distinct differences in transcriptomes between the genetically identical embryogenic tissues grown under the two epitype-inducing temperatures suggesting temperature-dependent canalizing of gene expression during embryo formation, putatively based on chromatin modifications. From 448 transcripts of genes coding for proteins involved in epigenetic machinery, we found 35 of these to be differentially expressed at high level under the epitype-inducing conditions. Therefore, temperature conditions during embryogenesis significantly alter transcriptional profiles including numerous orthologs of transcriptional regulators, epigenetic-related genes, and large sets of unknown and uncharacterized transcripts.
Authors
Callum Aidan Stephen HillAbstract
No abstract has been registered
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No abstract has been registered
Authors
Svein Øyvind Solberg Agnese Kolodinska Brantestam Madeleine Kylin Gitte Kjeldsen Bjørn Mette ThomsenAbstract
No abstract has been registered
Authors
Ermias Deribe Alemayehu Esayas Masresha Peder August Gade Siri Berger Bjørn Olav Rosseland Reidar Borgstrøm Elias Dadebo Gebremariam Zinabu Ole Martin Eklo Lindis Skipperud Brit SalbuAbstract
No abstract has been registered
Authors
Peder Gjerdrum Birger EikenesAbstract
Density is a fundamental softwood quality trait. The aim of this paper is to identify a spatial model for wood density variation in spruce stems, with the main focus on basic density. Six thousand 20-mm-wide cubes systematically sampled from 85 trees in western Norway were analysed. The overall radial density pattern was the J shape with local maximum in the pith and increasing density outwards from a minimum at some distance from the pith. The minimum appeared closer to the pith further up in the tree. The stochastic nature of the six tree-wise parameters defining density gradients from pith to surface and from base to top was analysed and described. The results provide information needed to simulate density variation inside stems and between stems in a population. Considering the fundamental influence of density on a range of wood traits, such simulation should be of great significance for scientific and industrial analyses.
Authors
Zahra Kalantari Steve W. Lyon Lennart Folkeson Helen French Jannes Stolte Per-Erik Jansson Mona SassnerAbstract
A physically-based, distributed hydrological model (MIKE SHE) was used to quantify overland runoff in response to four extreme rain events and four types of simulated land use measure in a catchment in Norway. The current land use in the catchment comprises arable lands, forest, urban areas and a stream that passes under a motorway at the catchment outlet. This model simulation study demonstrates how the composition and configuration of land use measures affect discharge at the catchment outlet differently in response to storms of different sizes. For example, clear-cutting on 30% of the catchment area produced a 60% increase in peak discharge and a 10% increase in total runoff resulting from a 50-year storm event in summer, but the effects on peak discharge were less pronounced during smaller storms. Reforestation of 60% of the catchment area was the most effective measure in reducing peak flows for smaller (2-, 5- and 10-year) storms. Introducing grassed waterways reduced water velocity in the stream and resulted in a 28% reduction in peak flow at the catchment outlet for the 50-year storm event. Overall, the results indicate that the specific effect of land use measures on catchment discharge depends on their spatial distribution and on the size and timing of storm events.
Abstract
No abstract has been registered
Abstract
New wood protection technologies should be effective against biodeterioration and at the same time minimize environmental impact. The present study investigates the effect of polyaniline modification of wood and the effect of a pulsed electric field on fungal protection. The effect of fungi and a pulsed electric field on the conductivity of the modified wood was also measured. It was found that it is possible to polymerize polyaniline particles in-situ homogeneously throughout the wood specimens. The polyaniline particles themselves were not found to be anti-fungal, however when in contact with water they affected the pH drastically and inhibited fungal growth. The wood treatment with polyaniline and the connection to a pulsed electric field were found to be effective in protecting the wood from deterioration when exposed to Postia placenta. The unmodified samples that were connected to a pulsed electric field lost under 10 wt% due to fungal degradation. The combination of polyaniline treatment with the connection to a pulsed electric field showed a slight synergistic effect which resulted in less weight loss due to fungal degradation. However, a more brittle wood structure was observed. Leached and fungal exposed samples showed a significant drop in the conductivity, indicating that the network has broken down slightly.
Abstract
© 2014. This is the authors’ accepted and refereed manuscript to the article.