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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.

2009

Abstract

There is a need to establish new objective and sensitive methods for early detection and quantification of decay fungi in wood materials. Molecular methods have proven to be a useful tool within wood protection issues, however, this field is still poorly explored and so far relatively few have used these methods within the field of wood deterioration. Among the techniques used in the indirect quantification of fungi in decayed wood and building material are chitin and ergosterol assays. DNA-based methods are rarely used for identification in connection with quantification. Access to knowledge about fungal colonisation paterns in different wood substrates would allow further improvement of new products. The aim of this study was to investigate the colonisation pattern of decay fungi in wood samples after six years in soil exposure, in an EN252 test.....

Abstract

One of the main challenges for modified wood and modified wood based WPCs (Wood Plastic Composites) is to predict accurate service life time in UC3 (Use class 3, above ground) and UC4 (in soil or fresh water contact). So far, data from in-service conditions are rare, while several studies have evaluated the durability in lab or field test exposure. However, there is still a lack of studies comparing replicate modified wood products in both field and lab exposure. This study evaluates the efficacy of modified wood and modified wood based WPCs in AWPA E10, three different types of soil in lab (ENV 807), three test fields in-ground (EN 252) and two test sites close to ground (horizontal double layer test)......

Abstract

Regulation of flowering time in Arabidopsis thaliana is controlled by a network of pathways integrating environmental and internal signals. Two of these pathways, the vernalization and photoperiodic pathways, mediate responses to prolonged cold period and photoperiod, respectively. A number of A. thaliana populations from high-latitude and high-altitude locations in Norway were collected and phenotyped for flowering time in response to 5 photoperiods and 5 vernalization treatments. Vernalization and photoperiodic sensitivity were not correlated with latitude but rather with climatic factors such as winter temperature and precipitation that do not vary with latitude, especially in coastal environments. Coastal populations, both from subarctic and intermediate latitudes, were rather insensitive towards the length of the vernalization treatment but very sensitive towards differences in photoperiods. Stronger photoperiod sensitivity in coastal populations might be a necessary adaptation for sensing the onset of spring in regions with relatively mild and unpredictable winter climates as opposed to continental climates with more stable winters. FLC sequence variation was only partly associated with vernalization response, whereas variation in transcript levels of CRY2, TOC1 and GI was correlated with photoperiodic responses. This suggests that local adaptation of populations may be partly mediated by photoreceptors and circadian clock pathways.

Abstract

One of the major concerns regarding use of velvet bentgrass in Scandinavia is whether current cultivars are sufficiently tolerant to frost. In 2008-09 the four velvet bentgrass (VB, Agrostis canina L.) cultivars Avalon, Greenwich, Legendary, and Villa, and the creeping bentgrass (CB, Agrostis stolonifera L.) cultivar Penn A-4 (control) were established from seed in 7.5x10x10 cm pots filled with a USGA-spec. sand containing 0.5% (w/w) organic matter. The following four treatments representing different phases of cold acclimation were compared: (i) nonacclimated (NA) plants maintained at 18 °C/12 °C (day/night) and 16 h photoperiod (150 μmol/m/s); (ii) plants acclimated at 2 °C and 16 h photoperiod (250 μmol/m/s) for 2 wk (A2); (iii) plants acclimated as ii plus 2 wk of sub-zero acclimation in darkness at -2 °C (A2+SZA2); and (iv) naturally acclimated plants under outdoor (field) conditions in November -December (FA). Freezing tolerance was assessed visually as percent of pot surface covered with healthy turf after 26 days of recovery in the greenhouse. To examine the relationship between physiological changes under cold acclimation and freezing tolerance, crowns of VB and CB were harvested for carbohydrate (CHO) analysis after each hardening treatment. Results showed that FA plants survived all freezing treatments (plant coverage more than 90 %). A2+SZA2 plants had better survival after freezing to -9 °C, -12 °C and -15 °C as compared with A2 plants. Differences in freezing tolerance between VB and CB were not significant. NA plants survived none of freezing temperatures. The predominant CHO in VB and CB crowns were sucrose and fructans. Compared with NA plants, A2 plants had significantly higher concentrations of fructose, sucrose and fructan. Exposure to -2 ºC in darkness (A2+SZA2) had no further effect on these concentrations. Natural hardening (FA) resulted in total carbohydrate and fructan concentrations significantly lower than for plants exposed to artificial acclimation.

Abstract

Continuous light is a promising method to reduce the problems with rose powderymildew in greenhouse rose production. The effects of such a light regime on the performance of insect pests on roses have so far not been investigated. In the present study, survival, developmental time, and reproduction during one generation of the greenhouse whitefly, Trialeurodes vaporariorum Westwood (Hemiptera: Aleyrodidae), were characterized on roses, Rosa x hybrida cv. Passion, grown in climate chambers with long-day conditions (L20:D4) or continuous light (L24:D0) at 21 oC and fluctuating relative humidity (mean 74%, range 47–96%). Whiteflies reared under continuous light had lower immature survival and fecundity and shorter female longevity than whiteflies reared under long-day conditions, but immature developmental time was only slightly affected. Life-table analysis showed that the net reproductive rate (Ro) and intrinsic rate of natural increase (rm) were reduced by 85 and 76%, respectively, and the time for the population to double its size (D) was 4.2 times longer under continuous light. Thismean that the whitefly population growth under continuous light was strongly reduced compared with the traditional light regime used in rose production.