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.
2012
Forfattere
Igor A. Yakovlev YeonKyeong Lee Adam Vivian-Smith Jorunn Elisabeth Olsen Carl Gunnar FossdalSammendrag
In Norway spruce there is an enigmatic epigenetic memory of the temperature conditions during embryogenesis affecting vital phenological traits (Yakovlev et al. 2012). Adaptive phenological traits such as bud burst and bud set, observed as clinal variation in nature, are the ones affected.The epigenetic memory is establishment exclusively during embryogenesis in response to environmental impact. The epitype fixated by the time the embryo is fully developed without any change in the primary DNA sequence and is mitotically propogated. The epigenetic mechanism influence the phenotype through altered regulation of gene expression and is propagated throughout every growth cycle for the entire lifespan of this long lived species.The epigenetic memory may be realized through several molecular mechanisms including DNA methylation, and histone modifications affecting chromatin, as well as by small non-coding RNAs, and may also be related to the mechanisms silencing transposable or repetitive elements in the genome. MicroRNAs (miRNAs), endogenous small regulatory RNAs, are shown to be differentially expressed in genetically identically but epigenetically different progenies, in regards to the timing of bud burst and bud set (Yakovlev et al. 2010).We have started large scale studies using next regeneration sequencing approaches to identify and characterize the genes and regulatory elements involved in the initiation, maintenance, and heritability of the epigenetic memory. Epigenetic related changes in miRNA regulation during the establishment of the epigenetic memory are now studied in in vitro derived somatic embryos developing under cold (18C) and warm (30C) environmental conditions (that induce epitypes).We have constructed and sequenced 10 small RNA libraries during proliferation, maturation stage 1, 2 3 and the mature stage of embryo formation in the contrasted temperatures, in two control libraries during proliferation at 22C, as well as their mRNA transcriptomes using the Ion Torrent PGMTM (Life technologies) platform.We are expecting to determine at what stage(s) during embryogenesis the epigenetic memory marks are being laid down by identifying when the transcriptomic differences, of small RNA and mRNAs, between the epitypes are the most prominent during embryogenesis. The identification of novel miRNA candidates and the confirmation of conserved and novel miRNAs will be presented.
Sammendrag
Det er ikke registrert sammendrag
Forfattere
Lars Sandved DalenSammendrag
Ulik geologi og grunnforhold forklarer variasjonen i kvaliteten på beiteområde i Hedmark.
Sammendrag
The combined effects of light, soil fertility, and ontogenetic changes on plant growth rates are poorly understood, yet these three factors play fundamental roles in structuring plant communities. We sought to determine how lodgepole pine (Pinus contorta Dougl. ex Loud. var. latifolia), interior spruce (Picea glauca engelmanii (Moench) Voss), and subalpine fir (Abies lasiocarpa (Hook.) Nutt.) sapling growth responds to the combination of light, soil fertility, and ontogeny and how these three dominant conifer species in sub-boreal forests of British Columbia differ in their responses.Using maximum likelihood methods, we found that 0.204 m tall sapling growth rates changed during ontogeny and were limited by both light and soil resources. The strongest differences among species growth rates were due to tree size, with smaller differences due to soil fertility, and there were no differences among species in the shape of their growth responses to light. Rank order in growth rates for small saplings (pine spruce fir) inversely corresponded to classic shade-tolerance ratings, thus supporting the carbon balance theory. Interior spruce height growth rates increased relative to lodgepole pine with increasing soil fertility, clearly matching the landscape-scale increase in canopy dominance of interior spruce over lodgepole pine with increasing soil fertility.
Forfattere
Bengt Gunnar Jonsson Juha Siitonen Jogeir N. StoklandSammendrag
Det er ikke registrert sammendrag
Sammendrag
De norske landskapene gror igjen og dette innvirker på en rekke verdiområder. Artikkelen diskuterer spesielt forholdet mellom gjengroing i kulturlandskapet og reiselivet i Norge.
Forfattere
Lars Sandved DalenSammendrag
Essay om det å være nervøs for å holde foredrag og hvordan det henger sammen med evolusjon.
Forfattere
Jørn Henrik Sønstebø Mari Mette Tollefsrud Øyvind Meland Edvardsen Ragnar JohnskåsSammendrag
Fjelledelgran (Abies lasiocarpa) er opprinnelig en nord-amerikansk art med et stort utbredelsesområde som strekker seg fra Alaska i nord til Arizona og New Mexico i sør. I Arizona, New Mexico og sørlige Colorado finnes korkedelgran (Abies lasiocarpa var. arizonica) som er en variant av fjelledelgran. I Norge er fjelledelgran et viktig tre for juletreproduksjonen. Arten har både gode juletreegenskaper og er godt tilpasset dyrking i det norske klimaet.
Sammendrag
This study examines already existing guidelines for the sustainable removal of slash from forests for bioenergy use. Existing guidelines from some countries, states and provinces with forest ecosystems comparable to Norways (Sweden, Finland, the U.K., Ireland, Minnesota, New Hampshire and British Columbia) are compared with the Norwegian Living Forests (LF) and Debio (ecological forestry) guidelines. The aim is to identify areas where the Norwegian guidelines could be further developed.
Forfattere
Peder GjerdrumSammendrag
Det er ikke registrert sammendrag