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.
2012
Authors
Nadeem Yaqoob Igor A. Yakovlev Paal Krokene Harald Kvaalen Halvor Solheim Carl Gunnar FossdalAbstract
We compared gene expression in Norway spruce secondary phloem (bark) and developing xylem (sapwood) in response to the necrotrophic pathogen Heterobasidion parviporum, wounding and methyl jasmonate (MeJ). The pathogen induced systemic and local up-regulation of PaPX3, PaPX2 and PaChi4 in both bark and sapwood that returned to constitutive levels as the plants recovered from the infection, whereas the local responses to MeJ were similar in both tissues but was longer lasting for PaPX3 and PaChi4. Genes involved in lignin biosynthesis (PaPAL1, PaPAL2, PaC4H3/5 and PaHCT1) were up-regulated locally in the bark in response to pathogen and wounding whereas MeJ induced a similar but stronger local response. The ethylene biosynthesis related transcripts PaACO and PaACS did not increase in response to MeJ treatment or the pathogen, however it increased both locally and systemically as a response to wounding in the sapwood. These results demonstrate that the local and systemic host responses to pathogen infection and wounding largely correspond and reveal striking similarities between the local response to a necrotroph, wounding and MeJ treatment in both bark and living wood.
Authors
Arnfinn Nes Hans Espelien Anne-Berit Wold Siv Fagertun RembergAbstract
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Authors
Alexander Kopatz Hans Geir Eiken Snorre Hagen Minna Ruokonen Rodrigo Esparza-Salas Julia Schregel Ilpo Kojala Martin Smith Ingvild Wartiainen Paul Eric Aspholm Steinar Wikan Alexander M. Rykov Olga Makarova Natalia Polikarpova Konstantin F. Tirronen Pjotr I. Danilov Jouni AspiAbstract
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Authors
Frans van den Berg A. Tiktak G. B. M. Heuvelink S. L. G. E. Burgers D. J. Brus F. de Vries Jannes Stolte J. G. KroesAbstract
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Authors
Bo Normander Gregor Levin Ari-Pekka Auvinen Harald Bratli Odd Egil Stabbetorp Marcus Hedblom Anders Glimskär Gudmundur A. GudmundssonAbstract
In 2002, world leaders made a commitment through the Convention on Biological Diversity (CBD), to achieve a significant reduction in the rate of biodiversity loss by 2010. At the Conference of the Parties of the CBD in Nagoya, Japan in 2010, the target was renewed for 2020. We have developed a Biodiversity Change Index (BCI) to help measure progress towards this target. The BCI is constructed with a two-dimensional resolution, allowing for a direct evaluation of the relative importance of changes in quantity and quality, respectively, to the overall change in biodiversity. Quantity is measured as the area of a specified habitat type and quality as the abundance of indicator species and other habitat quality parameters, such as the proportion of old trees or dead wood in forests. The BCI enables easy comparison of changes in biodiversity between different habitat types and between different regions and nations. We illustrate the use of BCI by calculating the index for the Nordic countries for two common habitat types, farmland and forest, and one habitat type of similar importance in the northern hemisphere; mires. In the period 1990–2005 declines in biodiversity of similar magnitudes are seen for farmland and mires across the Nordic countries, while for forest, trends vary considerably. Our results show that the BCI framework can be a useful tool to communicate the complex issue of biodiversity change in a simple manner. However, in accordance with other studies of biodiversity change we conclude that existing monitoring data are too scarce to consistently calculate BCI for all habitat types in all Nordic countries. In order to reasonably evaluate changes in biodiversity, further efforts towards monitoring programmes to obtain reliable and quality assured data on biodiversity at acceptable spatial and temporal resolutions are needed. Moreover, common methods to apply and harmonise data from different monitoring schemes should be developed.
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Abstract
Arable weeds are generally distributed in patches, while herbicides are applied uniformly. Herbicides can be saved if only the patches are sprayed, i.e. patch spraying (PS). Bottlenecks for cost-effective PS are weed monitoring technology and valid technology-based decision rules for PS (thresholds). The novel machine vision algorithm Weedcer has been developed as an efficient weed monitoring tool for PS. Weedcer estimates the proportions of young weed leaves and cereal leaves in high resolution red–green–blue images. We conducted field trials to test relative weed cover (RWC) and relative mayweed cover (RMC) estimated by Weedcer as decision rules for PS. RWC is the total weed cover divided by the total plant cover and RMC is the mayweed cover divided by the total plant cover. The main criterion for evaluation and basis of these thresholds was the measured grain yield. Images (about 0.06-m2) were acquired with a GPS guided autonomous field robot in spring, the normal time for spraying seed-propagated broadleaf weeds in both winter – and spring cereals in Norway. Three map-based trials (weed monitoring and spraying in two separate operations) showed that mean RWC per management unit (12.0 × 12.5-m) was generally adequate. In winter wheat heavily infested with scentless mayweed (Tripleurospermum inodorum (L.) Sch.Bip.) and/or scented mayweed (Matricaria recutita L.), the mean RMC per management unit was more adequate. Progress during the project allowed three additional trials conducted in real-time (weed monitoring and spraying in the same operation). These were conducted with the robot in spring cereals, and showed that a weighted moving average of RWC per image was adequate. The sprayed and unsprayed management units in these trials were minimum 3.0 × 3.0-m and 0.5 × 3.0-m, respectively. Results indicated that the Weedcer-based thresholds should be lower in wheat (Triticum aestivum) than in barley (Hordeum vulgare).