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.
2000
Authors
A. Sæbø Øystein JohnsenAbstract
No abstract has been registered
Abstract
The anatomical response of Norway spruce bark polyphenolic parenchyma cells (PP cells) to inoculation with the phytopathogenic fungus Ceratocystis polonica and attack by its bark-beetle vector Ips typographus was examined.Fungal inoculation on the periderm surface had no effect, while inoculation just below the periderm or halfway into the phloem (mid-phloem) generated detectable responses within 3 wk. The responses included increase in PP cell size and in periodic acid - Schiffs staining of PP cell phenolics, wound periderm initiation from PP cells, and cambial zone traumatic resin duct formation. Fungi were not seen in samples 3 wk after subperiderm or mid-phloem inoculation, but were found in some samples 6 and 9 wk after mid-phloem inoculation.In contrast, inoculations into the cambium resulted in partial (3 wk) or complete (6 and 9 wk) fungal colonization and death of tissue in the infected area. This indicates that PP cells have defenses capable of inhibiting fungal growth. Samples taken near bark-beetle galleries had similar anatomical responses as inoculated samples, validating the inoculation approach to studying defense responses in spruce.These results show that PP cells represent not only a constitutive defense system, but are also involved in local and remote inducible defenses against fungal and beetle attack.
Authors
Juha SiitonenAbstract
No abstract has been registered
Authors
Heleen A. de WitAbstract
No abstract has been registered
Abstract
No abstract has been registered
Authors
Jyrki TomminenAbstract
No abstract has been registered
Authors
Dan AamlidAbstract
Two fungi, V. heterodoxa and P. vaccinii, are found to have impact on the leaf coverage of bilberry plants. When studying vegetation or forest ecosystems, assessors should, therefore, be aware of the biotic impact of pathogens on plants.
Abstract
No abstract has been registered
Authors
Halvor TorgersenAbstract
This article describes an investigation of fatigue resistance in different steel wire rope constructions used in Norwegian cable logging operations. Test results indicate the following: A clear difference in fatigue resistance between ropes (approximately 50% decreased endurance for the compacted rope of highest density). Differences in rope wear for varying angles of deflection. A correlation between the number of visible broken wires and remaining strength in the rope.
Abstract
The present investigation deals with the properties of resonance wood destined for the production of musical instruments and with the methods for the determination of resonance wood quality. At the same time there are stated the range of values for the dynamic modulus of elasticity, for the speed of sound transmission and for the density of wood. The demands regarding dimension and growth characteristics of resonance wood are explained insisting first of all on pure subjective and visual criteria. The grading rules, existing only in a few regions in Germany, show that forestry is sensitized to this high value timber assortment only to a very small extent. With the Lucchimeter measuring method (elasticity tester) and the stress wave nondestructive evaluation technique spruce (Picea abies) and fir (Abies alba) wood panels are investigated which are destined for the production of guitars. The methods used as well as the results of measurement are compared with another. Furthermore the quantity of sales of resonance wood is presented after survey at the state owned forest management in Germany. The established small quantity of existing resonance wood is attributed to the sales of resonance wood not mentioned explicitly or described in detail. All in all the amount of resonance wood is supposed to be higher.