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.
2022
Abstract
Given the right climatic and environmental conditions, a range of microorganisms can deteriorate wood. Decay by basidiomycete fungi accounts for significant volumes of wood in service that need to be replaced. In this study, a short-wave infrared hyperspectral camera was used to explore the possibilities of using spectral imaging technology for the fast and non-destructive detection of fungal decay. The study encompassed different degradation stages of Scots pine sapwood (Pinus sylvestris L.) specimens inoculated with monocultures of either a brown rot fungus (Rhodonia placenta Fr.) or a white rot fungus (Trametes versicolor L.). The research questions were if the hyperspectral camera can profile fungal wood decay and whether it also can differentiate between decay mechanisms of brown rot and white rot decay. The data analysis employed Partial Least Squares (PLS) regression with the mass loss percentage as the response variable. For all models, the mass loss could be predicted from the wavelength range 1460–1600 nm, confirming the reduction in cellulose. A single PLS component could describe the mass loss to a high degree (90%). The distinction between decay by brown or white rot fungi was made based on spectral peaks around 1680 and 2240 nm, related to lignin.
Authors
Gry Alfredsen Christian Brischke Richard Acquah Tolgay Akkurt Per Otto Flæte Eva Frühwald Hansson Geir Wæhler Gustavsen Hasan Hosseini Targo Kalamees Jaan Kers Villu Kukk Roja Modaresi Jonas Niklewski Anna Sandak Sandak Jakub Philip van NiekerkAbstract
No abstract has been registered
Authors
Nina Elisabeth Nagy Hans Ragnar Norli Monica Fongen Runa Berg Østby Inger Heldal Jahn Davik Ari HietalaAbstract
Tree defense against xylem pathogens involves both constitutive and induced phenylpropanoids and terpenoids. The induced defenses include compartmentalization of compromised wood with a reaction zone (RZ) characterized by polyphenol deposition, whereas the role of terpenoids has remained poorly understood. To further elucidate the tree–pathogen interaction, we profiled spatial patterns in lignan (low-molecular-weight polyphenols) and terpenoid content in Norway spruce (Picea abies) trees showing heartwood colonization by the pathogenic white-rot fungus Heterobasidion parviporum. There was pronounced variation in the amount and composition of lignans between different xylem tissue zones of diseased and healthy trees. Intact RZ at basal stem regions, where colonization is the oldest, showed the highest level and diversity of these compounds. The antioxidant properties of lignans obviously hinder oxidative degradation of wood: RZ with lignans removed by extraction showed significantly higher mass loss than unextracted RZ when subjected to Fenton degradation. The reduced diversity and amount of lignans in pathogen-compromised RZ and decaying heartwood in comparison to intact RZ and healthy heartwood suggest that α-conindendrin isomer is an intermediate metabolite in lignan decomposition by H. parviporum. Diterpenes and diterpene alcohols constituted above 90% of the terpenes detected in sapwood of healthy and diseased trees. A significant finding was that traumatic resin canals, predominated by monoterpenes, were commonly associated with RZ. The findings clarify the roles and fate of lignan during wood decay and raise questions about the potential roles of terpenoids in signal transduction, synthesis, and translocation of defense compounds upon wood compartmentalization against decay fungi.
Abstract
No abstract has been registered
Abstract
No abstract has been registered
2021
Abstract
No abstract has been registered
Abstract
Composting and anaerobic digestion are the most common ways to treat organic residues. Sometimes the organic rest after anaerobic digestion is also composted. In this study we investigated greenhouse gas emissions from composting raw food waste compared to composting solid digestate of food waste. Cumulative methane emissions over 3 weeks were found to be almost 12 times higher from composting digested food waste than from raw food waste suggesting that the microbial community transferred from the anaerobic digestion to the compost process enhanced these emissions. Cumulative nitrous oxide emissions were also higher when composting solid digestate was compared to composting raw food waste, but the global warming potential was mostly driven by the impact of methane emissions. In conclusion, methane production during digestate composting can be high, therefore eliminating methane producing microbes in digestate before composting could be a promising way to reduce greenhouse gas emissions.
Abstract
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Abstract
The purpose of this research is to develop a method for estimating the spatially and temporally resolved moisture content of thermally modified Scots pine (Pinus sylvestris) using remote sensing. Hyperspectral time series imaging in the NIR wavelength region (953–2516 nm) was used to gather information about the absorbance of eight thermally modified pine samples each minute as they dried during a period of approximately 20 h. After preprocessing the collected spectral data and identifying an appropriate wavelength selection, partial least squares regression (PLS) was used to map the absorbance data of each pine sample to a distribution of moisture contents within the samples at different time steps during the drying process. To enable separate studying and comparison of the drying dynamics taking place within the early- and latewood regions of the pine samples, the collected images were spatially segmented to separate between early- and latewood pixels. The results of the study indicate that the 1966–2244 nm region of a NIR spectrum, when preprocessed with extended multiplicative scatter correction and first order derivation, can be used to model the average moisture content of thermally modified pine using PLS. The methods presented in this paper allows for estimation and visualization of the intrasample spatial distribution of moisture in thermally modified pine wood.
Abstract
No abstract has been registered