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
Roman Gebauer Daniel Volařík Josef Urban Isabella Børja Nina Elisabeth Nagy Toril Eldhuset Paal KrokeneAbstract
Conifer needles are extraordinarily variable and much of this diversity is linked to the water transport capacity of the xylem and to xylem conduit properties. However, we still know little about how anatomical characteristics influence the hydraulic efficiency of needle xylem in different parts of the crown. In this study we evaluated needle function and anatomy in Norway spruce families exposed to different light conditions. We measured tracheid and needle characteristics of sun-exposed and shaded current-year needles in two experimental plots: a control plot and a thinned plot with 50% reduction in stand density. Sun-exposed needles had a larger tracheid lumen area than shaded needles, and this was caused by a larger maximum tracheid lumen diameter, while the minimum lumen diameter was less plastic. Sun-exposed needles had also higher theoretical hydraulic conductivity than shaded needles. Thinning leads to increased radiation to the lower branches, and presumably exposes the upper branches to stronger water stress than before thinning. Thinning affected several needle parameters both in sun-exposed and shaded needles; tracheid lumens were more circular and minimum tracheid lumen diameter was larger in the thinned plot, whereas maximum tracheid lumen diameter was less plastic on both plots. This study demonstrates that needle xylem structure in Norway spruce is clearly influenced by the light gradient within the tree crown.
Authors
M. Lindblad T. Börjesson V Hietaniemi Oleif ElenAbstract
The relationship between weather data and agronomical factors and deoxynivalenol (DON) levels in oats was examined with the aim of developing a predictive model. Data were collected from a total of 674 fields during periods of up to 10 years in Finland, Norway and Sweden, and included DON levels in the harvested oats crop, agronomical factors and weather data. The results show that there was a large regional variation in DON levels, with higher levels in one region in Norway compared with other regions in Norway, Finland and Sweden. In this region the median DON level was 1000 ng g–1 and the regulatory limit for human consumption (1750 ng g–1) was exceeded in 28% of the samples. In other regions the median DON levels ranged from 75 to 270 ng g–1, and DON levels exceeded 1750 ng g–1 in 3–8% of the samples. Including more variables than region in a multiple regression model only increased the adjusted coefficient of determination from 0.17 to 0.24, indicating that very little of the variation in DON levels could be explained by weather data or agronomical factors. Thus, it was not possible to predict DON levels based on the variables included in this study. Further studies are needed to solve this problem. Apparently the infection and/or growth of DON producing Fusarium species are promoted in certain regions. One possibility may be to study the species distribution of fungal communities and their changes during the oats cultivation period in more detail.
Authors
HJ Van der Fels-Klerx Sonja Klemsdal V Hietaniemi M. Lindblad E Ioannou-Kakouri ED Van AsseltAbstract
This study aimed to investigate mycotoxin contamination of cereal grain commodities for feed and food production in North Western Europe during the last two decades, including trends over time and co-occurrence between toxins, and to assess possible effects of climate on the presence of mycotoxins. For these aims, analytical results related to mycotoxin contamination of cereal grain commodities, collected in the course of national monitoring programmes in Finland, Sweden, Norway and the Netherlands during a 20-year period, were gathered. Historical observational weather data, including daily relative humidity, rainfall and temperature, were obtained from each of these four countries. In total 6382 records, referring to individual sample results for mycotoxin concentrations (one or more toxins) in cereal grains were available. Most records referred to wheat, barley, maize and oats. The most frequently analysed mycotoxins were deoxynivalenol, 3-acetyl-deoxynivalenol, nivalenol, T-2 toxin, HT-2 toxin and zearalenone. Deoxynivalenol had the highest overall incidence of 46%, and was mainly found in wheat, maize and oats. Mycotoxins that showed co-occurrence were: deoxynivalenol and 3-acetyl-deoxynivalenol in oats; deoxynivalenol and zearalenone in maize and wheat; and T-2 toxin and HT-2 toxin in oats. The presence of both deoxynivalenol and zearalenone in wheat increased with higher temperatures, relative humidity and rainfall during cultivation, but the presence of nivalenol was negatively associated with most of these climatic factors. The same holds for both nivalenol and deoxynivalenol in oats. This implies that climatic conditions that are conducive for one toxin may have a decreasing effect on the other. The presence of HT-2 toxin in oats showed a slight decreasing trends over time, but significant trends for other toxins showed an increasing presence during the last two decades. It is therefore useful to continue monitoring of mycotoxins. Obtained results can be used for development of predictive models for presence of mycotoxins in cereal grains.
Authors
Carl Gunnar Fossdal Nina Elisabeth Nagy Ari Hietala Harald Kvaalen Rune Slimestad Steve Woodward Halvor SolheimAbstract
No abstract has been registered
Authors
Flavio Paoletti Antonio Raffo Kristian Thorup-Kristensen Randi Seljåsen Torfinn Torp Nicolaas Busscher Angelica Ploeger Johannes KahlAbstract
No abstract has been registered
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A survey of the prevalence of skin blemish diseases in potatoes after the growing seasons of 2008 and 2009 was carried out on 247 potato lots representing different cultivars and production regions in Norway. The results showed the presence of silver scurf (Helminthosporium solani) in all lots. Skin spot (Polyscytalum pustulans) and black scurf (Rhizoctonia solani) were found in 80% of the lots, and black dot (Colletotrichum coccodes) and common scab caused by Streptomyces spp. were present in 50–70%. Also, powdery scab (Spongospora subterranea) occurred in 65–80% of the lots, and root-lesion nematodes (Pratylenchus spp.) were detected in 60% of the sub-samples that exhibited symptoms of common scab.
Authors
Patrick Conaghan Pádraig O'Kiely Magnus Halling Frank O'Mara Lars NesheimAbstract
No abstract has been registered