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.
2002
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Leif Jarle Asheim Lars Olav Eik Ivar MysterudAbstract
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Authors
David Wei Zheng M. Freeman J. Bergh Ingvald Røsberg Petter NilsenAbstract
A process-based model was used to simulate biomass production of Norway spruce under both current climate and climate change scenarios. The model was parameterized for Nordmoen in south-east Norway using real climate data for the period 1987-1989. The model was applied to predict the biomass production responses to three climate change scenarios.The results showed that net primary production (NPP) increased by 7% under an elevated annual mean air temperature of 4C from the current 10.1 t dry mass ha-1 yr-1. A doubled current ambient CO2 concentration significantly increased NPP by 36%.The scenario of both elevated temperature and elevated CO2 concentration led to an increase in the NPP of 49%, higher than the sum of the two effects acting singly. The results also showed that forest production responses to climate change depend on the conditions of climate used for reference.
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The project reported here was a co-operation between the National Focal Centers for four of the ICPs in Norway: ICP Mapping and Modeling, ICP Waters, ICP Forest and ICP Integrated Monitoring. Dynamic modeling was carried out using data from several sites in the ICP networks, with the aim of making predictions on the future acidification status for surface waters, forest and soils in Norway. Predictions are made for three different deposition scenarios. At two of the sites, the model predictions suggest that the Current Legislation scenario will not promote water qualities sufficient for sustainable fish populations, while the scenario seems sufficient for the others. Under the Maximum Feasible Reduction scenario one of the sites still will not reach a sufficiently high ANC. In general, the modeling results for forest soils agree with results from previous investigations stating that surface water acidification is more severe than the soil acidification. However, the results suggest that there has been soil acidification at all sites as a result of acid deposition and that the base saturation will not be built up again to pre-industrial levels during the next 50 years at any of the sites, not even with the Maximum Feasible Reduction Scenario.
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Harald Kvaalen Ola Gram Dæhlen Ulrika EgertsdotterAbstract
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Academic – Quality seed – a factor for sustainable progress
JG Hampton, NM de Carvalho, M Kruse, ...
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No abstract has been registered
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Determining the level of pathogenic fungi and other microorganisms during colonization of the host is central in phytopathological studies. A direct way is to monitor fungal hyphae by microscopic examination, but indirect chitin and ergosterol-based assays have been among the most applied methods in determining fungal biomass within host tissues. Recently real-time technology is increasingly receiving attention as a way to follow infection agents in host tissues.We study the molecular basis of host defense responses, using the coniferous host Norway spruce (Picea abies) infected with the basidomycete Heterobasidion annosum as the experimental system. This basidiomycete is the major root rot causing pathogens in conifers of all age classes.In order to screen host material for differential resistance towards H.annosum for both scientific and commercial reasons, it is a necessity to reliably quantify the fungal colonization of the host tissues. Therefore, the aim of this study was to develop and compare the sensitivity of a real-time PCR assay to an ergosterol based method for determining the rate of colonization by H.annosum in inoculated spruce material. We also applied the methods to rank the infection level of the pathogen on the spruce tissue culture clones.We were able to develop a quantitative multiplex real-time PCR procedure that reliably detecting down to 1pg H.annosum DNA and 1ng host DNA in DNA extracted from infected tissues. There was a very high correlation between the fungal-biomass/total-biomass and fungal DNA-total DNA rankings obtained with ergosterol and real-time PCR respectively, strengthening the credibility of both methods.Based on both ergosterol and real-time PCR, it was clear that some spruce clones were faster and more heavily infected than others. These results indicate that both ergosterol and this real-time procedure can be useful methods to screen different spruce material for their relative resistance to the pathogen H.annosum.
Authors
H. Mäkinen P. Nöjd H.P. Kahle U. Neumann Bjørn Tveite K. Mielikäinen H. Röhle H. SpieckerAbstract
Regional and temporal growth variation of Norway spruce (Picea abies (L.) Karst.) and its dependence on air temperature and precipitation were compared in stands across latitudinal and altitudinal transects in southwestern and eastern Germany, Norway, and Finland.The temporal variation of radial growth was divided into two components: medium- and high-frequency variation, i.e. decadal and year-to-year variation, respectively. The medium-frequency component was rather different between regions, especially the southern and northern ones. However, within each region the medium-frequency growth variation was relatively similar, irrespective of altitudinal and latitudinal differences of the sample sites.A part of the high-frequency variation was common to all four regions, which suggests that some factors synchronising tree growth are common for the entire study area. The high-frequency component of growth was more strongly related to monthly air temperature and precipitation than was the medium-frequency variation. The limiting effect of low temperatures was more significant at northern as well as high-altitude sites, while the importance of precipitation increased in the south and at low altitudes.
Abstract
One of our main interests is to learn about the molecular basis of host defense responses, using the coniferous host Norway spruce infected with the pathogen Heterobasidion parviporum as the experimental system. This basidiomycete and the closely related pathogen H. annosum are the major root rot causing pathogens in conifers.To screen host material for differential resistance towards H. parviporum, it is a necessity to quantify the fungal colonization of the host tissues. Therefore, we aimed to develop and compare the sensitivity of a real-time PCR to an ergosterol based method for determining the rate of colonization. We developed a quantitative multiplex real-time PCR procedure that reliably detecting down to 1pg H. parviporum DNA and 1ng host DNA.There was a very high correlation between the fungal-biomass/total-biomass and fungal-DNA/total-DNA rankings obtained with ergosterol and real-time PCR, strengthening the credibility of both methods. The results indicate that this real-time procedure can be a useful method to screen different spruce material for their relative resistance to the pathogen H. parviporum.