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.
2019
Forfattere
Arne SteffenremSammendrag
Det er ikke registrert sammendrag
Forfattere
Arne SteffenremSammendrag
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Sammendrag
Det er ikke registrert sammendrag
Forfattere
Arne SteffenremSammendrag
Det er ikke registrert sammendrag
Sammendrag
The genus Scapania comprises a group of leafy liverworts distributed throughout many bryophytic assemblages. While many Scapania species grow widely, some are assessed as endangered and appear to be specialists with distinct niche environments. Several are found only in alpine forest communities, inhabiting decaying logs in streams, typical of an environment that is threatened by both logging activity and changes to watercourses. Another species, S. nimbosa, has an unusual Oceanic-Montane distribution across Ireland, Scotland, Norway, China and Nepal. Since gemmae and sexual reproduction are absent the species is hypothesized to be primarily dispersed by fragmentation. In Norway S. nimbosa occupies an area of only 13 x 20 km, at altitudes between 300-980 m, and is frequently found with another more abundant asexual species, S. ornithopodioides. This makes S. nimbosa susceptible to local extinction through climate change or perhaps interspecific competition. Genomics is being increasingly used to infer demography and the evolutionary history of a species. Ascertaining levels of genetic variation can also contribute towards an effective conservation management plan. Besides, very little is known about the genomic organization and sexual determination in leafy liverworts. To generate new knowledge about the genus Scapania we sequenced the genomes of the sexual species S. nemorea (both male and female isolates), S. undulata (a single isolate), and several asexual S. ornithopodiodes and S. nimbosa isolates. Illumina paired-end (2x 300 bp) and Oxford Nanopore long reads were used to create genomic references. Initially organellar genomes were assembled, annotated and genetic variation was discovered. This revealed that variation is indeed present even for S. nimbosa and S. ornithopodioides at Norwegian sites. Next we focussed on creating a high quality nuclear reference genome for S. nemorea using the SPAdes assembler (v3.13). Qualities of each assembly and isolate were assessed with QUAST and BUSCO. While one assembly spans 202.6 Mb (10930 scaffolds; N50 of 66 Kb), other isolates of S. nemorea show larger assembled genome sizes and different Kmer distributions, consistent with the expected alternative sexual chromosome complement. We further analyse genomic synteny and diversity, but emphasize that difficulties in extracting DNA from herbarium specimens really hamper analysis.
Forfattere
Tor MykingSammendrag
Det er ikke registrert sammendrag
Forfattere
Tor MykingSammendrag
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Forfattere
Volkmar Timmermann Kjell Andreassen May Bente Brurberg Isabella Børja Nicholas Clarke Daniel Flø Jane Uhd Jepsen Torstein Kvamme Jørn-Frode Nordbakken Per Holm Nygaard Martin Pettersson Sverre Solberg Halvor Solheim Venche Talgø Ole Petter Laksforsmo Vindstad Gro Wollebæk Bjørn Økland Wenche AasSammendrag
Source at <a href=http://hdl.handle.net/11250/2616613>http://hdl.handle.net/11250/2616613</a>
Sammendrag
Det er ikke registrert sammendrag
Sammendrag
Short-day (SD) treatment is used by forest nurseries to induce growth cessation in Picea abies seedlings. SD treatment may however increase the risk of reflushing in autumn and earlier bud break the following spring. When the start of the SD treatment is early in order to control seedling height, the duration of the SD treatment should be longer in order to prevent reflushing in autumn. However, due to the amount of manual work involved in the short-day treatment, increasing the number of days is undesirable from a practical point of view. Splitting the SD treatment could be a way to achieve both early height control and at the same time avoid autumn bud break with less workload. We tested how different starting dates and durations of SD treatment influenced on morphological and phenological traits. Regardless of timing and duration of the SD treatment, height growth was reduced compared to the untreated controls. Seedlings given split SD (7+7 days interrupted with two weeks in long days) had less height growth than all other treatments. Root collar diameter growth was significantly less in control seedlings than in seedlings exposed to early (7 or 14 days) or split (7+7 days) SD treatment. There were also differences in the frequency of reflushing and bud break timing among the SD treated seedlings, dependent on duration and starting date. If the SD treatment started early, a continuous 14-day SD treatment was not sufficient to avoid high frequencies of reflushing. However, by splitting the SD treatment into two periods of 7+7 days these negative effects were largely avoided, although spring bud break occurred earlier than in the controls.