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.
2006
Authors
Michelle de Chantal Kjersti Holt Hanssen Aksel Granhus Urban Bergsten Mikaell Ottosson-Löfvenius Harald GripAbstract
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According to previous studies, short day (SD) treatment may increase frost hardiness in Picea abies (L.) Karst. seedlings during shoot elongation the next year. The purpose of this study was to examine how timing of the SD treatment affects spring frost hardiness. The following four treatments were applied in the first growth period: natural photoperiod (Nat), or SD treatment (8/16 h, day/night) either from 14-28 July (SD1), 28 July-11 August (SD2), or 11 20 August (SD3). After 125 days in the cold store (October-January), the seedlings were transferred to forcing conditions (20-25oC, 24 h photoperiod) followed by freezing tests at 3, -5, -7 and 9oC when most seedlings had reached bud break stage 7 (Krutzsch index). Seedling height measurements and analyses of carbohydrate status, nitrogen concentration and dry weight of needles after cold storage were done to examine the treatments` impact on seedling quality. SD treatment reduced visual freezing injury to current- and first-year shoots. Mortality occurred at –7 and –9oC and was significantly higher in treatments Nat and SD1 (43% in both) than in the SD2 (23%) and SD3 (15%) treatments. Seedlings from the late SD treatments also showed better height growth and developed more shoots from dormant buds after freezing to –3 and –5oC. Collectively, these findings demonstrate the importance of proper timing of the SD treatment in relation to the seedlings’ natural growth rhythm.
Abstract
A method for quantitative determination of extractives from heartwood of Scots pine (Pinus sylvestris L.) using gas chromatography (GC) with flame ionization detection (FID) was developed. The limit of detection (LOD) was 0.03mg/g wood and the linear range (r=0.9994) was up to 10mg/g with accuracy within ±10% and precision of 18% relative standard deviation. The identification of the extractives was performed using gas chromatography combined with mass spectrometry (GC–MS). The yields of extraction by Soxhlet were tested for solid wood, small particles and fine powder. Small particles were chosen for further analysis. This treatment gave good yields of the most important extractives: pinosylvin, pinosylvin monomethyl ether, resin acids and free fatty acids. The method is used to demonstrate the variation of these extractives across stems and differences in north–south direction.
Authors
Fride Høistad ScheiAbstract
No abstract has been registered
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When using chitosan as an antifungal agent in wood it is important to understand which factors contribute to a higher fixation ratio to optimize the utilization of chitosan, the active component. Small pine samples were impregnated with chitosan solutions varying in molecular weight, concentration, pH, polymerization agent, acid and degree of deacetylation. Different post-treatments such as time, temperature, moisture content and the effect of present air were applied to the samples to evaluate the effect on the relative retention. After impregnation, the samples, with a volume of 1.5 cm3, were leached in separate test-tubes according to EN-84. The samples were prepared in a paired design where both samples were impregnated, but only one was leached. Both leached and unleached samples were analysed for their chitosan content, and the relative ratio was used as a measure for the relative retention of chitosan during leaching. The results from these trials show that pH in the range of 5.1-5.9 is favourable. The molecular weight should be as high as possible yet able to penetrate the wood structure, and the use of acetic acid gives far better fixation than the use of hydrochloric acid.
Authors
Erik LarnøyAbstract
No abstract has been registered
Authors
Andreas TreuAbstract
No abstract has been registered