Publikasjoner
NIBIOs ansatte publiserer flere hundre vitenskapelige artikler og forskningsrapporter hvert år. Her finner du referanser og lenker til publikasjoner og andre forsknings- og formidlingsaktiviteter. Samlingen oppdateres løpende med både nytt og historisk materiale. For mer informasjon om NIBIOs publikasjoner, besøk NIBIOs bibliotek.
2017
Forfattere
Eduarda Molina-Alcaide Maria Dolores Carro Michael Roleda Martin Riis Weisbjerg Vibeke Lind Margarita Novoa-GarridoSammendrag
Seaweeds have potentials as alternative feed for ruminants, but there is a limited knowledge on their nutritive value. Seven seaweed species collected along the coast above the Arctic circle of Norway, both in spring and autumn, were assessed for nutrients and total polyphenols (TEP) content, gas production kinetics and in vitro rumen fermentation in batch cultures of ruminal microorganisms. The seaweeds were three red species (Mastocarpus stellatus, Palmaria palmata and Porphyra sp.), three brown species (Alaria esculenta, Laminaria digitata and Pelvetia canaliculata) and one green species (Acrosiphonia sp.). Additionally, the abundance and diversity of total bacteria, protozoa and archaea in the cultures with the three red seaweeds collected in spring were analyzed by quantitative PCR and PCR-DGGE, respectively. The crude protein (CP) content varied widely. Pelvetia had the greatest (P < 0.001) ether extract (EE) content. Non-structural carbohydrates (NSC) content varied from 135 to 541 g/kg DM with brown seaweeds having the greatest values. Ash and CP contents were higher in spring than in autumn (P = 0.020 and 0.003, respectively), whereas concentrations of EE and NSC were not affected by collecting season (P = 0.208–0.341). The TEP values ranged from 1.46 to 50.3 mg/g dry matter (DM), and differed (P < 0.001) among seaweed species and collecting season, being greater in autumn than in spring. The DM effective degradability (DMED), estimated from gas production parameters for a rumen passage rate of 3.0% per h, ranged from 424 to 652 g/kg, the highest values were recorded for Mastocarpus stellatus and Porphyra sp. The lowest DMED values were registered for Pelvetia canaliculata and Acrosiphonia sp. In 24-h incubations (500 mg DM), Palmaria palmata had the highest (P < 0.05) volatile fatty acids (VFA) and methane production (4.34 and 0.761 mmol, respectively) and the lowest (P < 0.05) final pH values and acetate to propionate ratios (6.57 and 2.34, respectively). There were no differences (P > 0.05) among the other seaweeds in VFA production, but Porphyra sp. had the second highest methane production (P < 0.05; 0.491 mmol) compared with the other seaweeds (0.361 mmol; averaged value). The methane/total VFA ratio was not affected (P > 0.05) by either seaweed species or the collection season. Higher final pH (P < 0.05) and lower (P < 0.05) methane and VFA production, ammonia-N concentrations and DMED values were promoted by the fermentation of seaweed collected in autumn compared with those from spring. Among the red seaweeds, there were no species-specific differences (P > 0.05) in the abundance or the diversity of total bacteria, protozoa and archaea. In the PCR-DGGE analysis, samples were separated by the incubation run for all microbial populations analyzed, but not by seaweed species. The results indicate that seaweed species differ markedly in their in vitro rumen degradation, and that samples collected in autumn had lower rumen degradability than those collected in spring.
Sammendrag
Det er ikke registrert sammendrag
Forfattere
Laura Jaakola Laura Zoratti Nga Nguyenquynh Lara Giongo Katja Karppinen Anne Linn Hykkerud Eivind Uleberg Inger Martinussen Hely HäggmanSammendrag
Det er ikke registrert sammendrag
Forfattere
Sigridur Dalmannsdottir Marit Jørgensen Marcin Rapacz Liv Østrem Arild Larsen Rolf Rødven Odd Arne RognliSammendrag
The effect of variable autumn temperatures in combination with decreasing irradiance and daylength on photosynthesis, growth cessation and freezing tolerance was investigated in northern- and southern-adapted populations of perennial ryegrass (Lolium perenne) and timothy (Phleum pratense) intended for use in regions at northern high latitudes. Plants were subjected to three different acclimation temperatures; 12, 6 and 9/3°C (day/night) for 4 weeks, followed by 1 week of cold acclimation at 2°C under natural light conditions. This experimental setup was repeated at three different periods during autumn with decreasing sums of irradiance and daylengths. Photoacclimation, leaf elongation and freezing tolerance were studied. The results showed that plants cold acclimated during the period with lowest irradiance and shortest day had lowest freezing tolerance, lowest photosynthetic activity, longest leaves and least biomass production. Higher acclimation temperature (12°C) resulted in lower freezing tolerance, lower photosynthetic activity, faster leaf elongation rate and higher biomass compared with the other temperatures. Photochemical mechanisms were predominant in photoacclimation. The northern-adapted populations had a better freezing tolerance than the southern-adapted except when grown during the late autumn period and at the highest temperature; then there were no differences between the populations. Our results indicate that the projected climate change in the north may reduce freezing tolerance in grasses as acclimation will take place at higher temperatures and shorter daylengths with lower irradiance.
Forfattere
Stef Bokhorst Laura Jaakola Katja Karppinen Guro Kristine Edvinsen Hanne Mæhre Jarle W. BjerkeSammendrag
Main conclusion Evergreen plants are more vulnerable than grasses and birch to snow and temperature variability in the sub-Arctic. Most Arctic climate impact studies focus on single factors, such as summer warming, while ecosystems are exposed to changes in all seasons. Through a combination of field and laboratory manipulations, we compared physiological and growth responses of dominant sub-Arctic plant types to midwinter warming events (6 °C for 7 days) in combination with freezing, simulated snow thaw and nitrogen additions. We aimed to identify if different plant types showed consistent physiological, cellular, growth and mortality responses to these abiotic stressors. Evergreen dwarf shrubs and tree seedlings showed higher mortality (40–100%) following extreme winter warming events than Betula pubescens tree seedlings and grasses (0–27%). All species had growth reductions following exposure to − 20 °C, but not all species suffered from − 10 °C irrespective of other treatments. Winter warming followed by − 20 °C resulted in the greatest mortality and was strongest among evergreen plants. Snow removal reduced the biomass for most species and this was exacerbated by subsequent freezing. Nitrogen increased the growth of B. pubescens and grasses, but not the evergreens, and interaction effects with the warming, freezing and snow treatments were minor and few. Physiological activity during the winter warming and freezing treatments was inconsistent with growth and mortality rates across the plants types. However, changes in the membrane fatty acids were associated with reduced mortality of grasses. Sub-Arctic plant communities may become dominated by grasses and deciduous plants if winter snowpack diminishes and plants are exposed to greater temperature variability in the near future. C-repeat binding factor · Fatty acids · Frost · Grass · Multiple stresses · Shrub · Snow
Sammendrag
Det er ikke registrert sammendrag
Forfattere
Mohammad Ramin Marcia De Oliveira Franco Michael Roleda Inga Marie Aasen Mårten Hetta Håvard SteinshamnSammendrag
Det er ikke registrert sammendrag
Sammendrag
Det er to viktige innfallsporter til Møysalen nasjonalpark og Møysalen landskapsvernområde. Begge disse er vurdert og sammenlignet i denne sårbarhetsanalysen. Den mest brukte går fra vest via Lonkanfjorden, inkludert båtskyss inn fjorden. Denne strekningen går delvis på gammel gruvevei. Til fots starter egentlig stien fra Felten og følger Lonkanfjorden inn i Norddalen. Den vurderte strekningen slutter der oppstigingen til Memuruskardet tar til, ettersom det foreligger planer for klopplegging og omlegging av sti opp skardet. Innfallsport fra sør via Forkledalen starter ved parkering langs E10 i Ingelsfjordeidet og går opp til toppen av Memuruskardet der den møter sti opp fra Norddalen. Begge innfallsportene er delt opp i to strekninger i sårbarhetsvurderingen.
Sammendrag
Important factors for development of quality defects are the physical, physiological and chemical state of the tubers, which is also described as the maturity status of the crop. The use of maturity indicators as predictors of quality in potato tubers during and after storage was explored in cvs. Asterix and Saturna with three different maturity levels during three years (2010, 2012 and 2013). The maturity indicators measured 1–3 weeks before harvest and at harvest included haulm senescence (haulm maturity), skin set (physical maturity), dry matter content (physiological maturity) and contents of sucrose, glucose and fructose (chemical maturity). Potato quality parameters were measured three times during storage (December, February and April) and included dry matter content, sucrose, glucose and fructose contents, weight loss and fry colour. Cultivar and maturity level were included as categorical predictors in a linear regression model and contributed significantly (P < 0.001) to the models predicting reducing sugars during storage. Dry matter, sucrose, glucose and fructose were included as continuous predictors in the linear regression models and contributed significantly (P < 0.01) to the sucrose, glucose and fructose models and these models explained a high proportion of the variation (R2 ≥ 0.88). Skin set contributed significantly to the weight loss models (P < 0.01) but the models showed low R2 -values (R2 < 0.48). Sucrose contents contributed significantly (P = 0.05) to the fry colour model for Asterix and the fry colour models for both Asterix and Saturna had R2 -values of 0.50 and 0.51 respectively. This study provides new information about the influence of maturity on potato quality during storage and the potential of using field measurements of maturity as predictors of storage potential for processing potato cultivars Asterix and Saturna in Norway.
Sammendrag
Vekta på traktorar og utstyr har auka mykje sidan eldre feltforsøk med jordpakking i eng vart utført i Noreg. Vi har undersøkt korleis køyring med dagens traktorar påverkar jordfysiske forhold, avling, plantesetnad og fôrkvalitet av rein graseng og kløverblanda eng i ein forsøksserie på tre einingar i NIBIO, på Tjøtta i Nordland, på Fureneset i Sunnfjord og på Løken i Valdres. Traktorkøyring gav stor avlingsnedgang (20 %) på siltjord i Valdres, medan nedgangen var meir moderat (6 %) på siltig sandjord på Fureneset og det var ingen avlingseffekt på sandjord med god luftveksling på Tjøtta. Det var små forskjellar mellom bruk av lett eller tung traktor, og resultata viser at ein i størst mogleg grad bør unngå køyring under våte forhold på jord som er utsett for pakkingsskade. Køyring på siltjord førte til endringar i den botaniske samansetnaden i enga ved at raudkløver og tofrøblada ugras gjekk tilbake og kvitkløver og grasugras gjekk fram. Køyring på siltjord reduserte også opptak og fiksering av nitrogen. Bruk av kløver i frøblandinga gav stor positiv effekt på avling, protein- og mineralinnhald og gav lågare fiberinnhald i fôret. Bruk av 6 kg N i mineralgjødsel etter førsteslått gav god avlingseffekt, men reduserte kløverinnhald og biologisk nitrogenfiksering. Sterkare nitrogengjødsling og bruk av kløver endra grasbestanden i enga i retning av meir timotei og mindre engsvingel. Auke i såmengda av kløver frå 15 % til 30 % på vektbasis gav små utslag på avling og botanisk samansetjing, men auka Nfikseringa med 0,5 kg per dekar og år.