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
Authors
Vibeke Lind Jan Berg Lars Olav Eik Jørgen A.B. Mølmann Espen Haugland Marit Jørgensen Margrethe HerslethAbstract
Many consumers perceive lamb meat from mountain pastures to be of superior quality, a quality that may be altered if lambs are kept for a longer period on cultivated pastures before slaughtering. The objective of this experiment was to compare sensory profile and fatty acid composition in meat from lambs slaughtered directly from unimproved mountain pastures with meat from lambs raised on unimproved mountain pastures and fattened on biodiverse cultivated pastures for 26, 39 and 42 days before slaughtering. The experiment was conducted at two different locations in Norway in 2006 and 2007, with a total of 124 Norwegian Crossbred Sheep lambs. Loin samples of M. Longissimus dorsi from lambs above a body weight of 40 kg were selected and analysed for sensory attributes. Fatty acid composition was determined in the subcutaneous fat over the Longissimus dorsi. Small but significant differences were found in hardness, tenderness, fattiness, metallic and rancid flavour, and in polyunsaturated fatty acids. This indicates that to a small extent pre-slaughter fattening on cultivated pastures alters meat characteristics. (C) 2009 Elsevier Ltd. All rights reserved.
Authors
Lars Sekse Mekjell Meland T. Reinsnos S. VestrheimAbstract
Fruit samples of seven sweet cherry cultivars grouped into three different groups of fruit flesh firmness (soft-fruited: 'Ranna Ljaskovska', 'Vista' and 'Sunburst', medium firm: 'Ulster' and 'Sylvia' and firm cultivars: 'Van' and 'Lapins') were harvested over a three week period with 3-4 d intervals prior to, during and after normal harvest time in 1997 and 1998 in Ullensvang, western Norway. Fruit firmness was measured at each harvest date along with measurements of soluble solids content (SSC), air temperature, precipitation and estimation of fruit colour. Corresponding samples picked at normal harvest date were stored in normal air atmosphere at temperatures 2 degrees C and 8 degrees C, respectively, and firmness was measured during storage with 3-5 d intervals. All the tested cultivars reached normal firmness, colour and SSC at harvest both years. Fruit were generally darker in 1998 than in 1997. All cultivars showed a more or less distinct reduction in firmness over the period prior to and slightly after normal harvest. Exceptions were 'Sunburst' in the 1998-season, that increased in firmness after normal harvest date, and the two firmest cultivars that increased in firmness over the ripening period in 1997. Generally, firmness increased during the first part of storage followed by a decrease after 1-2 weeks, the decrease being usually earlier and more distinct at 8 degrees C than at 2 degrees C. 'Van' in 1998 showed no change in firmness development throughout the storage period but a small increase in the last part. 'Lapins' in 1997 had however, a pronounced drop in firmness in the middle of the storage period followed by an increase. All the tested cultivars were more firm at normal harvest time in 1998 than in 1997, except the two firm-fleshed cultivars 'Van' and 'Lapins'. The warm and sunny 1997-summer produced softer fruits than the cold and rainy 1998-season, except for the firm-fleshed cultivars. It was anticipated that the many contradictory results of sweet cherry fruit firmness reported by other authors may be caused by differences in weather conditions as demonstrated.
Abstract
Growth and flowering of the annual-fruiting raspberry (Rubus idaeus L.) cultivar 'Polka' were studied under controlled environment conditions in order to facilitate out-of-season production. Vegetatively-propagated plants originating from adventitious root buds were used. Height growth and the rate of leaf formation increased with increasing temperature, up to a broad optimum in the mid-20 degrees C range. While elongation was consistently enhanced by long-day (LD) conditions, photoperiod had no effect on the rate of leaf formation. LD stimulation of growth thus resulted from increased internode length only. In agreement with earlier reports, it was found that, in contrast to biennial-fruiting cultivars, such annual-fruiting cultivars do not need low temperatures for flower initiation, nor do they appear to have a juvenile phase during which they are un-responsive to flower-inducing conditions. 'Polka' plants responded to inductive conditions as early as the 5-leaf stage, and flowered freely across the entire range of growth temperatures, even at 30 degrees C. Flowering was advanced and the number of flowers increased with increasing temperature, up to an optimum at 27 degrees C. Flowering was also consistently advanced and occurred at lower nodes under LD than under short-day (SD) conditions across the whole range of temperatures. Night interruption for 3 h in the middle of the night was also effective, demonstrating that this is a true photoperiodic response and not merely an effect of increased light integral in LD. It was also confirmed that a distinct vernalisation-type advancement of flowering took place when small, non-dormant plants were exposed to additional chilling at 6 degrees C for several weeks. At low temperatures, a large proportion of the lateral buds were dormant, so that, at 12 degrees C, the plants actually flowered only at their tips. Dissections also revealed that the dormant buds had initiated flowers; but, because of their dormant state, they needed several weeks of chilling before they could flower (biennial-fruiting behaviour). Both types of buds were initiated by the same environmental conditions. Practical applications of the findings are suggested.
Abstract
Environmental control of flowering and runnering in three contrasting Fragaria chiloensis populations with geographic origins in Alaska, Oregon, and Chile have been studied under controlled environment conditions. All populations were principal short-day (SD) plants at intermediate temperatures (15 degrees C or 21 degrees C), while at low temperature (9 degrees C) the 'Alaska' and 'Chile' populations were essentially day neutral. However, the populations had contrasting temperature responses for flowering in SD at both constant and fluctuating day/night temperatures. At a day temperature of 18 degrees C, flowering increased with increasing night temperature from 9 degrees C to 21 degrees C in the 'Alaska' population, while the opposite trend was observed in the 'Chile' population. The sparsely flowering 'Oregon' population flowered only in SD within a narrow range of temperatures (15-18 degrees C). Photoperiod (10, 16, or 20 h) had no effect on flower development at 18 degrees C. All populations were runnering freely, but with different temperature and photoperiod modifications. It is concluded that the SD X temperature interaction in the flowering behaviour of the June-bearing cultivated strawberry, F. X ananassa, is inherited to a large extent from F. chiloensis, whereas the species does not appear to have contributed to the long-day (LD) flowering control in everbearing cultivars.
Authors
Svein Solberg Andreas Brunner Kjersti Holt Hanssen Holger Lange Erik Næsset Miina Rautiainen Pauline StenbergAbstract
In this study we demonstrate how airborne laser scanning (ALS) can be applied to map effective leaf area index (LAI(e)) in a spruce forest, after being calibrated with ground based measurements. In 2003 and 2005, ALS data and field estimates of LAI(e) were acquired in a Norway spruce forest in SE Norway. We used LI-COR's LAI-2000 (R) Plant canopy analyzer ("LAI-2000") and hemispherical images ("HI") for field based estimates of LAI(e). ALS penetration rate calculated from first echoes and from first and last echoes was strongly related to field estimates of LAI(e). We fitted regression models of LAI(e) against the log-transformed inverse of the ALS penetration rate, and in accordance with the Beer-Lambert law this produced a linear, no-intercept relationship. This was particularly the case for the LAI-2000, having R-2 values > 0.9. The strongest relationship was obtained by selecting ALS data from within a circle around each plot with a radius of 0.75 times the tree height. We found a slight difference in the relationship for the two years, which can be attributed to the differences in the ALS acquisition settings. The relationship was valid across four age classes of trees representing different stages of stand development, except in one case with newly regenerated stands which most likely was an artifact. Using LAI(e) based on HI data produced weaker relationships with the ALS data. This was the case even when we simulated LAI-2000 measurements based on the HI data. (C) 2009 Elsevier Inc. All rights reserved.
Abstract
In trees adapted to cold climates, conditions during autumn and winter may influence the subsequent timing of bud burst and hence tree survival during early spring frosts. We tested the effects of two temperatures during, dormancy induction Mid mild spells (MS) during chilling, on the timing of bud burst in three Picea abies (L.) Karst. provenances (58-66 degrees N). One-year-old seedlings were induced to become dormant at temperatures of 12 or 21 degrees C applied during 9 weeks of short days (12-h photoperiod). The seedlings were then moved to cold storage and given either continuous chilling at 0.7 degrees C (control), or chilling interrupted by one 14-day MS it either 8 or 12 degrees C. Interruptions with MS were staggered throughout the 175-day chilling period, resulting in 10 MS differing in date of onset. Subsets of seedlings were moved to forcing conditions (12-h photoperiod, 12 degrees C) throughout the chilling period, to assess dormancy status different timings of the MS treatment. Finally, after 175 days of chilling, timing of bud burst was assessed in a 24-h photoperiod at 12 degrees C (control and MS-treated seedlings). The MS treatment did not significantly affect days to bud burst when given early (after 7-35 chilling days). When MS was given after 49 chilling days or later, the seedlings burst bud earlier than the controls, and the difference increased with increasing length of the chilling period given before the MS. The 12 degrees C MS treatment was more effective than the 8 degrees C MS treatment, and the difference remained constant after the seedlings had received 66 or more chilling days before the MS treatment was applied. In all provenances, a constant temperature of 21 degrees C during dormancy induction resulted in more dormant seedlings (delayed bud burst) than a constant temperature of 12 degrees C, but this did not delay the response to the MS treatment.
Abstract
No abstract has been registered
Abstract
The estrogenic mycotoxin zearalenone (ZON) produced by some Fusarium spp. causes reproductive problems and hyperestrogenic syndromes in mammals. In an effort to elucidate the molecular pathways of ZON production, we present a comparative real-time quantitative polymerase chain reaction expression study of seven contiguous genes in the ZON biosynthetic cluster on sterile rice and during wheat and oat infection. Under ZON production on rice, the polyketide synthase (PKS) genes PKS4 and PKS13, alcohol oxidase FG12056 gene, and transcriptional regulator FG02398 gene showed similarly upregulated patterns, whereas the nonribosomal peptide synthetase (NPS) FG02394, the K+ channel beta subunit FG12015, and the protein kinase FG02399 displayed a variant pattern. During the same time period under wheat infection when no ZON was produced, the PKS genes and the NPS were downregulated relative to rice whereas the K+ channel beta subunit gene FG12015 was markedly upregulated, suggesting that it may play a role in the infection process. This is the first expression study of ZON biosynthetic genes in planta. The results give insight into the regulation and activities of the ZON gene cluster under different experimental systems and suggest a connection between ZON and a K+ channel that could reveal a novel function for ZON in Fusarium spp.
Authors
Arve Heistad Razak Seidu Andreas Svarstad Flø Adam Paruch Jon Fredrik Hanssen Thor-Axel StenströmAbstract
Tie long-term use of a filter-based, on-site wastewater treatment system increases nutrient discharge to receiving waters and may reduce its hygienic barrier efficiency. The main purpose of this research was to assess the hygienic barrier efficiency and the associated health risks of an on-site system that had exceeded its 5-yr design capacity with respect to phosphorus (P) removal. The system was investigated for bacteria and virus removal and assessed with respect to potential health risks in relation to reuse of effluent for irrigation. The system consists of a septic tank, a pressure-dosed vertical flow biofilter, and an up-flow filter unit with lightweight clay aggregates. The total P concentration in the effluent had increased gradually from initially <0.1 mg P L-1 during the first 2 yr of operation to 1.8 mg P L-1 after 5.3 yr. Escherichia coli was used as an indicator organism for fecal bacteria removal, whereas bacteriophages phi X174 and Salmonella typhimurium phage 28B (S.t. 28B) were used to model enteric virus removal. An overall decrease in E. coli removal occurred from a complete (approximately 5.6 log(10)) reduction during the first 3 yr of operation to 2.6 log(10) reduction. The removal amounts of the bacteriophages phi X174 and S.t. 28B were 3.9 and 3.7 log(10), respectively. Based on removal of S.t. 28B, the risks of rotavirus infection and disease for the investigated scenarios were above the acceptable level of 10(-4) and 10(-3), respectively, as defined by the World Health Organization.
Authors
Knut Anders Hovstad Silje Borvik Mikael OhlsonAbstract
In modern agricultural landscapes, large herbivores are often restricted in their mobility or are found at low densities, and other animal vectors may therefore be important for seed dispersal. In our study, a range of plant species were able to disperse by attaching seeds to, and having their seeds retained in, the fox fur some distance. We suggest that the red fox may be an important vector for epizoochorous seed dispersal in the agricultural landscape.