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.
2001
Authors
Harald Kvaalen Erik Christiansen Øystein Johnsen Halvor SolheimAbstract
Genetic associations between initiation of embryogenic tissue (ET) and susceptibility to the phytopathogenic fungi Ceratocystis polonica (Siem.) C. Moreau and Heterobasidion annosum (Fr.) Bref. in Norway spruce have been studied by initiating ET from zygotic embryos of mature seeds collected from 19 clones tested for susceptibility to the pathogens in a clonal field trial.Initiation frequencies varied significantly among clones (families), ranging from 12 to 56%. The family variance component accounted for more than 40% of the total variance in initiation frequency of ET. The estimates of broad-sense heritability of fungus susceptibility of the clones ranged from 0.12 for length of phloem necrosis after low-density inoculation with H. annosum to 0.55 for blue-stained sapwood after mass inoculation with C. polonica.None of the susceptibility measures showed any phenotypic correlation with initiation of embryogenic tissue. Genetic correlations and their standard errors were estimated by bootstrapping. Two measures of fungal susceptibility correlated genetically with initiation of ET; estimated at 0.58 for lesion length after inoculation with C. polonica and 0.29 for H. annosum lesion length. A better measure of susceptibility, blue-stained sapwood following inoculation with C. polonica, was not correlated with initiation of ET.
Abstract
Air pollution induced changes in pine needle chemistry were observed at sample sites in the surroundings of the Pechenganikel smelter. Close to the smelter, elevated concentrations of Ni, Cu and S were found (Ni: 0.7-1 mmol/kg, CU: 0.4-0.5, and S 40-60 mmol/kg) Close to the pollution source needles were enriched in Ni and Cu by needle age. Correlation and principal component analyses show that changes in the element composition of pine needles depended on air pollution and on natural factors as well. The contribution from air pollution increased with needle age. Besides direct input of pollutants from atmosphere, soil contamination and nutritional disturbance contributed significantly to the observed changes.
Authors
Jenny Fäldt Halvor Solheim Bo Långström Anna-Karin Borg-KarlsonAbstract
No abstract has been registered
Abstract
No abstract has been registered
Authors
Toril Drabløs Eldhuset Berit Swensen Heleen A. de Wit Nina Davidsen Gro WollebækAbstract
No abstract has been registered
2000
Authors
V.R. Nsolomo Halvor Solheim Kåre Olav VennAbstract
No abstract has been registered
Abstract
Aluminium (Al) has been considered to be a central element for risk evaluation of forest damage due to acidification. It has been hypothesised that Al reduces root growth, nutrient uptake and forest vitality. However, forest monitoring studies fail to show correlations between soil acidification and forest health. In general, no direct relation between Al concentration and forest health has been established. Here, Al concentrations in soil solution were manipulated by weekly additions of dilute AlCl3 to levels that are believed to be unfavorable for plant growth. Four treatments (in triplicate) including a reference and three Al addition levels were established. Effects of enhanced Al concentrations on fine root growth, nutrient uptake and crown condition in a mature Norway spruce forest in Norway were tested (1996-1999). After three years of manipulation, crown condition, tree growth and fine root growth were not affected by potentially toxic Al concentrations. However, the Mg content in current year\"s needles decreased at the highest Al addition treatment. The Mg/Al ratio of fine roots of the same treatment had declined too, which suggests that Al blocked Mg uptake at the root surface. The manipulation will be continued for two more years.
Authors
Dan Aamlid Natalya Vassilieva Per Arild Aarrestad Michael L. Gytarsky S. Lindmo Rodion Karaban Vladimir Korotkov Tord K. Rindal V. Kuzmicheva Kåre Olav VennAbstract
Six sites for forest ecosystem monitoring were established to perform a long-term study of effects of air pollution on pine forest ecosystems along a pollution gradient in the border areas between Norway and Russia. The main pollution source is a nickel smelter.Several methods and analyses were used to investigate different compartments of this northern boreal forest ecosystem. The differences in ecological condition and diversity observed among the research sites are probably due to the air pollution load in the area. The elevated concentrations of Ni and Cu detected in plant tissues, the reduced lichen vegetation on stems and on the forest floor, and the reduced or absent moss vegetation are the most obvious impacts in the investigated area.
Authors
V.R. Nsolomo Halvor Solheim Kåre Olav VennAbstract
No abstract has been registered
Authors
Erik Christiansen Alan A. Berryman Vincent R. Franceschi Trygve Krekling Paal Krokene Nina Elisabeth Nagy Halvor SolheimAbstract
No abstract has been registered