Publikasjoner
NIBIOs ansatte publiserer flere hundre vitenskapelige artikler og forskningsrapporter hvert år. Her finner du referanser og lenker til publikasjoner og andre forsknings- og formidlingsaktiviteter. Samlingen oppdateres løpende med både nytt og historisk materiale. For mer informasjon om NIBIOs publikasjoner, besøk NIBIOs bibliotek.
2002
Forfattere
Harald Kvaalen Ola Gram DæhlenSammendrag
Det er ikke registrert sammendrag
Sammendrag
A quantitative multiplex real-time PCR procedure was developed to monitor the dynamics in Norway spruce (Heterobasidion annosum) pathosystem. The assay reliably detected down to 1 pg of H. annosum DNA and 1 ng of host DNA in multiplex conditions. As a comparative method for quantifying fungal colonization,we applied the ergosterol assay. There was a very high correlation between the results obtained with the two methods, this strengthening the credibility of both assays. The advantages and disadvantages of these assays are discussed.
Sammendrag
Determining the level of pathogenic fungi and other microorganisms during colonization of the host is central in phytopathological studies. A direct way to monitor fungal hyphae within the host is microscopic examination, but chitin and ergosterol-levels are commonly used to indirectly measure the amount of fungus present. Recently real-time PCR technology is being used to follow infection agents in host tissues. We study 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, and applied the methods to rank the infection level of the pathogen on the spruce clones 053 and 589. 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. Based on both ergosterol and real-time PCR, it was clear that the clone 053 was hosting more fungal biomass than clone 589. 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.
Sammendrag
Det er ikke registrert sammendrag
Forfattere
O. Kiikkilä J, Derome T. Brügger Christian UhligSammendrag
In order to assess the success of in situ remediation of coniferous forest soil polluted by a Cu-Ni smelter, the total Cu concentration in soil percolation water, the fluxes of Cu down through the soil profile, and the toxicity of soil percolation water to soil bacteria was studied. Total Cu in percolation water was also fractionated into free ionic and complexed forms. The toxicity of the percolation water was measured by the [3H]-thymidine incorporation method, which measures bacterial growth rates. Soil percolation water was collected during one growing season by zero tension lysimeters inserted in the soil at 0.2 and 0.4 m in the soil. The treatments consisted of a control, mulch application to the forest floor (M) and a mulch application after removing the polluted organic soil layer (MR). The mulch consisted of a mixture of compost and woodchips (1/1; vol/vol). Analyses of Cu species and dissolved organic carbon (DOC) indicated that DOC leached from the mulch and complexed Cu into forms that were less toxic to soil bacteria. At 0.2cm depth percolation water toxicity was 19% lower in the M and 42% lower in the MR than in the control. Toxicity correlated with the Cu2+ concentration, which was 61 and 84% lower in the M and MR treatments, respectively, compared to the control. However, there were signs that total Cu had leached down through the soil profile, the leaching being more pronounced in the MR treatment.
Sammendrag
This study shows that it is questionable if critical load modelling can contribute in the search for harmful effects of acid deposition on forest health at present. Critical loads for S and N deposition were calculated using the MAGIC and PROFILE models for more than 100 monitoring plots in Norway spruce forest in south-east Norway. The two models gave different results, likely due to differences in the models, including differences in the time spans applied. The PROFILE model gave considerably more plots with exceedance than the MAGIC model. At plots where the CL was exceeded, calcium/aluminium (Ca/Al) ratios in the soil solutions were low. However, very few of these plots had possible harmful values of the Ca/Al-ratio. More than 50 yr seems in most cases to be needed to bring Ca/Al ratios below 1.0. Present deposition was better correlated with measured forest condition variables such as crown condition and needle chemistry, than with modelled exceedance according to any of the two methods. The deposition of S and N was weakly, negatively correlated to foliar concentrations of P and Ca, and positively to foliar N concentrations and crown density.
Forfattere
May-Guri SaethreSammendrag
Det er ikke registrert sammendrag
Forfattere
Hugh RileySammendrag
§ Bruk av husdyrgjødsel er sammenlignet med ulike kombinasjoner av N, P og K i mineralgjødsel på morenejord i Vang, Hedmark, siden 1922. Avlingsresultater for de siste fem årene er presentert her. § Avlingene uten gjødsel ligger i snitt på halvparten av nivået som en fikk ved bruk av 10 kg N, 2,5 kg P og 12 kg K pr. dekar § Av enkeltstoffene gav bruk av nitrogen fortsatt størst avlingsøkning, etterfulgt av fosfor og så kalium. Begge de sistnevnte viste positivt samspill med nitrogen § Ved bruk av fastgjødsel fra en biodynamisk gård, gav årlige mengder av 2, 4 og 6 tonn pr. dekar henholdsvis 84%, 94% og 97% av avlingsnivået en fikk med mengdene N, P og K som er nevnt ovenfor, gitt i mineralform § Balanse mellom tilførsel og bortførsel av nitrogen fikk en ved bruk av noe over 5 kg N/daa/år i mineralgjødsel, og med noe under 2 tonn husdyrgjødsel/daa/år
Forfattere
Nina Elisabeth NagySammendrag
Det er ikke registrert sammendrag
Sammendrag
Isoproturon is a herbicide which is fairly soluble in water and is considered a risk compound for leaching to surface and ground water. The fungicide metalaxyl is even more water soluble than isoproturon and can be rapidly leached from sandy soil that are low in organic matter. Transformation rates of isoproturon and metalaxyl in a silty clay loam and a sandy loam from Norway have been studied in the laboratory as well as in the field. Production of the metabolites monodesmethyl-isoproturon, didesmethyl-isoproturon and the acid-metabolite of metalaxyl were also monitored.