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.
2008
Abstract
Whereas lichen growth rates have received considerable attention, comparatively few detailed studies of growth patterns have been carried out. Generally, most lichens seem to grow apically, with pseudomeristomatic tissue confined to lobe margins and branch tips. However, some species appear to retain the capacity to expand throughout the thallus. Such intercalary growth processes have proved difficult to confirm in the field for two- and three-dimensionally growing folious and fruticose forms. Using transplants of the conspicuous, one-dimensionally growing Usnea longissima Ach., we document that intercalary growth actually does occur, with thalli expanding geometrically in length with a doubling time of less than a year under favorable conditions.
Authors
Anders Lunnan Inge Stupak Antti Asikainen Karsten Raulund-RasmussenAbstract
Forest bioenergy is utilisation is closely related to issues of pronounced political importance such as energy policies and international processes for sustainable management, especially climate change and sustainable forest management. The book chapter discusses both aspects and end up by summing up the contributions of the WOOD-EN-MAN project.
Authors
Berit Nordskog David M. Gadoury May Bente Brurberg Tor Håkon Sivertsen R. Kennedy Arne HermansenAbstract
No abstract has been registered
Authors
Toril Drabløs EldhusetAbstract
Oxalate exuded constitutively by Picea abies / Laccaria bicolor may lead to rhizosphere oxalate concentrations relevant for Al resistance.
Authors
Daniel Kwaku A. Asante Anne-Katrine Ree Rosnes Anna Holefors Ragnhild Nestestog Stein E. Lid Jørgen A. Mølmann Jorunn Elisabeth Olsen Øystein Johnsen Olavi Junttila Carl Gunnar FossdalAbstract
Studies have implicated the involvement of the phytochrome light receptors in adaptation of trees to light climate, but the molecular basis of this in gymnosperms is less understood. The promoter regions of plant genes are modular and contain a number of cis-acting elements, each of which may contribute to one or more aspects of a complex expression profile. As a step towards characterization of Norway spruce phytochromes at the transcript level, we isolated fragments (between 700-1500 bp upstream of their putative ATG translational start) of phytochrome N, O and P promoters...
Abstract
No abstract has been registered
Abstract
No abstract has been registered
Abstract
For subsurface solute transport, flux concentrations are key, while usually resident concentrations are measured. Flux concentrations are frequently estimated from resident concentrations by temporal moment analysis. We tested this approach by simulating transport of an injected tracer during steady flow in an aquifer with a heterogeneous saturated hydraulic conductivity. We constructed grid-cell scale breakthrough curves (BTCs) from flux concentrations and approximate BTCs from resident concentrations and estimated flux concentrations. We assembled these BTCs into spatio-temporal leaching surfaces at various aquifer cross-sections for subsequent analysis. Resident concentrations were unsuitable to assess solute movement in the aquifer. Temporal moment analysis worked well when the entire aquifer cross-section was considered, but performed poorer at the grid-cell scale because it approximates the local velocity by the trajectory average. The leaching surfaces served as valuable tools to demonstrate and quantify the limitations of temporal moment analysis.
Abstract
Insect-induced damages in forests are a major concern for timber production, landscape conservation and ecosystem research. Early detection methods based on remote sensing data can document the severity and spatial extent of ongoing attacks and might aid in designing mitigation measures or even prevention where necessary. In southeastern Norway, a large-scale insect defoliation of pine trees is ongoing. The larvae of the Pine sawfly Neodiprion sertifer reate it with its mass attacks during their feeding on needles in June and July. In the winter before the attack, egg galleries are evident in the needles. This provides a test case for early detection methods and remote sensing techniques for monitoring forest health....
Abstract
Recent in situ 13C studies suggest that lignin is not stabilised in soil in its polymerised form. However, the fate of its transformation products remains unknown. The objective of the present research was to provide the first comprehensive picture of the fate of lignin-derived C across its transformations processes: (1) C remaining as undecomposed lignin molecules, (2) C in newly formed humic substances, i.e. no longer identifiable as lignin-polymer C, (3) C in microbial biomass, (4) C mineralised as CO2, and (5) dissolved organic C. To achieve this objective, we designed an incubation experiment with 13C-labelled lignin where both elementary and molecular techniques were applied. Lignin was isolated from 13C labelled maize plants (13C-MMEL) and incubated in an agricultural soil for 44 weeks. Carbon mineralisation and stable isotope composition of the released CO2 were monitored throughout the incubation. Microbial utilisation of 13C-MMEL was measured seven times during the experiment. The turnover rate of the lignin polymer was assessed by 13C analysis of CuO oxidation products of soil lignin molecules. After 44 incubation weeks, 6.0% of initial 13C-MMEL carbon was mineralised, 0.8% was contained in the microbial biomass, and 0.1% was contained in dissolved organic C form. The compound-specific 13C data suggest that the remaining 93% were overwhelmingly in the form of untransformed lignin polymer. However, limited transformation into other humic substances potentially occurred, but could not be quantified because the yield of the CuO oxidation method proved somewhat variable with incubation time. The initial bacterial growth yield efficiency for MMEL was 31% and rapidly decreased to plateau of 8%. A two-pool first-order kinetics model suggested that the vast majority (97%) of MMEL lignin had a turnover time of about 25 years, which is similar to field-estimated turnover times for soil-extractable lignin but much longer than estimated turnover times for fresh plant-residue lignin. We conclude that natural lignin structures isolated from plants are rather unreactive in soil, either due to the lack of easily available organic matter for co-metabolism or due to enhanced adsorption properties. The data also suggest that fairly undecomposed lignin structures are the main reservoir of lignin-derived C in soils.