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
Abstract
Epiphytic lichen vegetation on birch stems was studied in the border areas between Norway and Russia. The area is heavily influenced by sulphur dioxide pollution emitted from Russian nickel smelters.Hypogymnia physodes and Melanelia olivacea were the two most abundant lichen species on birch stems in the investigated area. However, the coverage of H. physodes and M. olivacea was clearly reduced in parts of the investigated area. The lichen vegetation increased with increasing distance from the pollution source, i.e. from a lichen desert to normal background levels. A different pattern of occurrence of the two lichen species was observed.
Authors
Isabella BørjaAbstract
No abstract has been registered
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
Lars Sandved Dalen Carl Gunnar Fossdal Inger Heldal Nina Elisabeth Nagy Praveen Sharma Geir Østreng Anders Lönneborg Øystein JohnsenAbstract
Plants are sessile and have to adjust to the prevailing environmental conditions of their surroundings. This has led to a development of a great plasticity in gene regulation, morphogenesis, and metabolism. Adaptation and defence strategies involve the activation of genes encoding proteins important in the acclimation or defence towards the different stressors.Some of the molecular responses to biotic and abiotic stress factors such as pathogenic fungi or drought are specific, but it has also been shown that similar genes are acitvated by several stressors.At the Norwegian Forest Research Institute we are currently developing a diagnostic tool using the induction pattern of several selected genes from Norway spruce to use as a fingerprint for different types of biotic and abiotic stress. The ultimate goal of this project is to be able to identify unique mRNA expression patterns specific for different stressors such as heat, cold, drought, pathogens etc.In order to study the induction pattern expressed under biotic and abiotic stress, Norway spruce seedlings grown on glass beads in a phytotron we have treated with drought, a root pathogenic fungi (Rhizoctonia sp.), and a combination of drought and the root fungal pathogen.Physiological measurements of height, weight, ion leakage, gas exchange, and chlorophyll fluorescence are taken troughout the experiment. In addition, we have used light and electron microscopy, and immunolocalization to study structural cell and tissue changes. The results so far show great variance in the expression patterns between treatments and over time.
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.