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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.

2018

Sammendrag

Dei semi-naturlige naturtypane Boreal hei og Semi-naturlig eng er vurdert som sårbar VU, mens Kystlynghei og Semi-naturlig strandeng er vurdert som sterkt trua EN. Strandeng er vurdert som sårbar VU. Slåttemark er vurdert som kritisk trua CR fordi arealet av denne naturtypen har gått kraftig tilbake siste femti år. Semi-naturlige naturtypar er avhengige av riktig skjøtsel for å oppretthalde artsmangfaldet og økologiske funksjonar, og den dominerande påverkingsfaktoren for alle dei vurderte naturtypane er endringar i jordbruket og mangel på skjøtsel som er nødvendig for å oppretthalde naturtypane.

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Cloudberry (Rubus chamaemorus L.) is a wild perennial shrub growing on peatland with a circumpolar distribution. The combined berries have a high polyphenol content comprised primarily of ellagitannins. A few commercial cultivars are available, and pre-breeding trials on clonal material from different geographical origins are in progress. The objective of this study was to investigate how the content of polyphenols of four different cloudberry cultivars were affected by harvesting time and climatic variations during a 3-year-period. Plants were grown outside in plots and berries were harvested when mature. Berries were analyzed for total polyphenols and total anthocyanins by spectrophotometer. Total ellagic acid was identified and quantified using HPLC-MS after hydrolysis of the extracts. Results showed that all measured parameters; total anthocyanins, total polyphenols and ellagic acid are strongly influenced by the genetic background. Although low anthocyanin contents were present in all genotypes, they were highly affected by climatic conditions, being highest at low temperatures. However, the content of ellagic acid was less affected by environmental conditions and showed little response to changing temperatures. In conclusion, ellagitannin content was the most dominating polyphenol group observed in this study and was affected by genetics and is therefore a good breeding criterion for increased health benefit of cloudberry.

Sammendrag

Rhodiola rosea is a perennial flowering plant with a long history as a medicine plant. The plant contain a range of bioactive compounds including salidroside, rosavin, rosarian and rosin. Some of the compounds are characterized as adaptogens, meaning they can increase the body’s resistance to various stressors. An increased demand for better pharmaceuticals has stimulated the development of new methods for agricultural as well as in vitro cultivation of medicinal plants. A new technology, called rhizosecretion of biologically active chemicals, can provide a continuous supply of biologically active compounds over the lifetime of plants. The plants will then be grown under controlled conditions. In order to increase the production of bioactive compounds in Rhodiola rosea under these conditions it is therefore hypothesized that the biosynthesis can be upregulated by growing it under specific temperature and light quality treatments. An experiment with different light and temperature regimes was established for optimal accumulation of biologically active compounds. Four different clones of Rhodiola rosea were grown under three different light conditions (red, blue and white) combined with two different temperatures (9 and 18 °C) for three weeks. The gene expression of Tyrosine decarboxylase (TyrDC), found to have a key role in the biosynthesis of salidroside, were investigated. In addition, the content of various bioactive compounds were quantified before and after treatment. The results indicate that use if high producing clones is most important for high production and that there is a short-term upregulation during blue light treatment. During the three-week treatment, there was no significant effect of the temperature treatments.

Sammendrag

Increasing species diversity often promotes ecosystem functions in grasslands, but sward diversity may be reduced over time through competitive interactions among species. We investigated the development of species’ relative abundances in intensively managed agricultural grassland mixtures over three years to identify the drivers of diversity change. A continental-scale field experiment was conducted at 31 sites using 11 different four-species mixtures each sown at two seed abundances. The four species consisted of two grasses and two legumes, of which one was fast establishing and the other temporally persistent. We modelled the dynamics of the four-species mixtures over the three-year period. The relative abundances shifted substantially over time; in particular, the relative abundance of legumes declined over time but stayed above 15% in year three at many sites. We found that species’ dynamics were primarily driven by differences in the relative growth rates of competing species and secondarily by density dependence and climate. Alongside this, positive diversity effects in yield were found in all years at many sites.

Sammendrag

Weed suppression was investigated in a field experiment across 31 international sites. The study included 15 plant communities at each site, based on two grasses and two legumes, each sown in monoculture and 11 four-species mixtures varying in the relative proportions of the four species. At each site, one grass and one legume species was selected as fast establishing and the other two species were selected for persistence. Average weed biomass in mixtures over the whole experiment was 52% less (95% confidence interval, 30 to 75%) than in the most suppressive monoculture (transgressive suppression). Transgressive suppression of weed biomass persisted over each year for each mixture. Weed biomass was consistently low and relatively similar across all mixtures and years. Average sown species biomass was greater in all mixtures than in any monoculture. The suppressive effect of sown forage species on weeds in mixtures was achieved without any herbicide use. At each site, weed biomass for almost every mixture was lower than the average across the four monocultures. The average proportion of weed biomass in mixtures was less than in the most suppressive monoculture in two thirds of sites. Mixtures outyielded monocultures, and mixture yield comprised far lower weed biomass.

Sammendrag

Slåttemark har status som trua naturtype jfr. naturmangfoldloven. Restaurering og skjøtsel av resterende artsrike slåttemarker er tids- og ressurskrevende siden de er ofte små, bratte eller grunnlendte. Samtidig har det blitt anbefalt å etterligne mest mulig det tradisjonelle bruksregimet som inkluderer ljåslått (eller tohjulstraktor), bakketørking/hesjing og fjerning av graset for å sikre det biologiske mangfoldet. Tilskuddsordningen for trua naturtyper skal stimulere til å restaurere og holde verdifulle slåttemarkene i hevd ved å gi tilskudd til den arbeidskrevende slåtten. For å få flest mulige lokaliteter bevart for framtiden er det viktig at arbeidsmengden og krav om utstyr og håndtering av graset under restaurering og skjøtsel er overkommelig uten at det går på bekostning av artsmangfoldet. Hovedmålsettingen med prosjektet var å undersøke hva slags effekt økt mekanisering av slått har på artsmangfoldet i verdifull slåttemark ved å erstatte bruk av ljå og tohjulstraktor med ryddesag eller beitepusser......

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Carbonic anhydrase (CA) plays an important physiological role in all biological systems by accelerating the interconversion of CO2 and HCO3 −. In algae, CA is essential for photosynthesis: external CA (CAext) dehydrates HCO3 −, enhancing the supply of CO2 to the cell surface, and internal CA (CAint) interconverts HCO3 − and CO2 to maintain the inorganic carbon (Ci) pool and supply CO2 to RuBisCO. We frst conducted a literature review comparing the conditions in which CA extraction and measurement have been carried out, using the commonly used Wilbur–Anderson method. We found that the assay has been widely modifed since its introduction in 1948, mostly without being optimized for the species tested. Based on the review, an optimized protocol for measuring CA in Macrocystis pyrifera was developed, which showed that the assay conditions can strongly afect CA activity. Tris–HCl bufer gave the highest levels of CA activity, but phosphate bufer reduced activity signifcantly. Bufers containing polyvinylpyrrolidone (PVP) and dithiothreitol (DTT) stabilized CA. Using the optimized assay, CAext and CAint activities were readily measured in Macrocystis with higher precision compared to the non-optimized method. The CAint activity was 2×higher than CAext, which is attributed to the Ci uptake mechanisms of Macrocystis. This study suggests that the CA assay needs to be optimized for each species prior to experimental work to obtain both accurate and precise results.

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Although pasture is low-cost feed, many farmers find it difficult to maintain high milk yield when using pasturefor high-yielding dairy cows in automatically milked herds. Therefore, a seven-week experiment with 40 cows inearly to mid-lactation was performed to evaluate a management model for including pasture in the diet withoutjeopardizing milk production. Within a part-time grazing system with morning and evening outdoor access, wecompared a group with ad libitum grass silage indoors combined with access to a small grass-covered permanentpaddock for exercise and recreation (group EX) with a group offered production pasture at a high allowance percow and day combined with restricted grass silage allowance at night (group PROD). Both groups had the sameoutdoor access times and the same concentrate allowance based on pre-experimental milk yield. Milk yield andmilking frequency were recorded daily in the automatic milking unit. Milk recordings and samplings for de-termination of milk composition took place weekly and outdoor behaviour of cows was recorded during pastureaccess hours on six observation days, evenly distributed over the experimental period. During the experiment,average metabolisable energy concentration was higher in the grass silage offered both groups than in pastureherbage. However, our results showed no significant difference in daily milk yield between treatments.Furthermore, no signifi cant differences between treatments were found in energy-corrected milk, milk fatproduction, or body weight change. Milk protein production was, however, significantly higher in group PROD.In early lactation, no difference in milking frequency was observed between treatments while for cows in mid- tolate lactation, milking frequency was significantly higher in group EX than group PROD. Over the entire ex-periment, group EX cows spent significantly less time outdoors than group PROD. In conclusion, offering highyielding dairy cows in automatic milking systems high-quality pasture at a high allowance for a few hours inmorning and afternoon appears to be an interesting alternative to exercise paddock with full indoor feeding, as itcan reduce costs for supplementary silage, facilitate natural behaviour, and encourage cows to spend more timeoutdoors, while maintaining milk production at a level comparable to that of full indoor feeding.

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Sammendrag

The aim of the "Arctic as a food producing region" - project is to assess the potential for increased production and added value of food from the Arctic region, with the overarching aim of improving economic and social conditions of Arctic communities. This report is the output from the first phase of the project, providing a description of the main food production and examples of conditions for food production in the Arctic areas of the countries involved. This will form the basis for further analysis of opportunities, driving forces and barriers for further development of arctic food production, in the next phase of the project. The project has participation from Canada, Denmark, Greenland, Iceland, Norway and Russia, and is endorsed by the Arctic Council Sustainable Development Working Group (SDWG).