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.
2008
Forfattere
Daniel Kwaku A. Asante Igor A. Yakovlev Carl Gunnar Fossdal Anna Holefors Lars Opseth Jorunn Elisabeth Olsen Olavi Junttila Øystein JohnsenSammendrag
Short days (SD) trigger cessation of elongation growth and transition from an actively growing apex to a terminal bud in woody plants of the temperate and boreal zones. The molecular basis behind this is not well understood in gymnosperm forest trees such as Norway spruce. By combining suppression subtractive hybridization (SSH) libraries and monitoring of gene expression using quantitative RT-PCR analysis, we aimed to identify genes involved in photoperiodic control of growth cessation and dormancy induction in Norway spruce. The gene expression patterns described here will be useful for future detailed functionalanalyses.
Sammendrag
The Fusarium genus includes devastating plant pathogenic fungi that cause diseases in cereals around the world. They produce several mycotoxins, including the estrogenic compound zearalenone. To better understand the molecular mechanisms determining zearalenone production, we performed differential display RT-PCR under conditions where Fusarium graminearum and F. culmorum produced high amounts of zearalenone. We found 133 expressed sequence tags (ESTs) and 54 of these were considered to be up-regulated during high zearalenone production. Several of the ESTs were confirmed to be up-regulated by real-time qPCR, but none showed any significant down-regulation in the zearalenone negative mutant Delta PKS4-T9, or were similar to typical gene expression patterns of previously described zearalenone-related genes. Some of the up-regulated ESTs were similar to genes involved in secondary metabolite production, lipid metabolism, transcriptional activation, provision of precursors, signal transduction, transport or detoxification. Several of the ESTs were also located adjacent to one another in the genome and therefore might represent genes involved in the same biosynthetic pathway. Members of six such putative pathways could be found. All sequences were compared to the MIPS F. graminearum Genome Database to verify autocalled gene predictions experimentally and to introduce new exons and gene structures.
Forfattere
Bernt-Håvard ØyenSammendrag
Det er ikke registrert sammendrag
Forfattere
H. Dupré de Boulois Erik J. Joner C. Leyval I. Jakobsen B.D. Chen P. Roos Y. Thiry G. Rufyikiri B. Delvaux S. DeclerckSammendrag
Det er ikke registrert sammendrag
Forfattere
Thomas Hartnik Bjarne StyrishaveSammendrag
Det er ikke registrert sammendrag
Sammendrag
Det er ikke registrert sammendrag
Forfattere
Yijie WuSammendrag
Luftforurensninger og klimaendringer påvirker kjemien i kronedrypp og jordvann i boreale skoger. Løst organisk materiale (DOM), inklusiv løst organisk karbon (DOC) og løst organisk nitrogen (DON), spiller en nøkkelrolle, og det er derfor nødvendig å forstå hvordan DOM blir påvirket, ikke bare av luftforurensninger og klimatiske faktorer, men også av andre faktorer. Denne avhandling undersøker faktorer som påvirker DOC og DON i norske skogøkosystem, med bruk av data fra de norske ICP Forests Level II-flater og andre studier...
Sammendrag
Quota regulations that prevent output expansion of farms and reallocation of output between farms can cause lower growth in output and productivity. The aim of this study was to explain the output growth rate of Norwegian dairy farms since 1976, and to decompose it into output, input, socioeconomic and technical change components. Instead of using the standard distance function approach for multi-output technologies, we use a growth rate formulation, which automatically removes the farm-specific effects. This formulation also helps to impose non-negativity constraints on marginal products of inputs (input elasticities), which are often violated for many observations, especially when flexible functional forms are used. The farm-level panel data cover three periods: before the quota scheme was introduced (1976-1982); the period with the most output-restricting quota scheme (1983-1996); and the period with a more flexible quota scheme (from 1997 onwards). Results show that the milk quota regulations had a significant constraining effect on output growth, in particular on milk output in the period 1983-1996. Furthermore, the output mix has shifted towards meat production for the average farm. What emerges from this study is that output growth and technical change are negatively influenced by policy aims where productive performance has not been the primary objective, and that there is scope for increased farm growth if the quota regime is liberalised.
Sammendrag
The most important and widespread disease on golf courses is Microdochium nivale. Attempt to control the disease is mainly by prophylactic spraying with fungicides in fall. The aim of this project has been to understand how inoculum of M. nivale survives from spring to fall and to clarify the efficiency of selected fungicides. Snow mould symptoms and the occurrence of M. nivale in leaves and stems of grasses sampled from golf greens and foregreens was reduced during the growth season. We also found that M. nivale could be isolated from locations without visible symptoms. Despite a lower isolation rate in autumn, M. nivale was again isolated in some of the originally locations, the following spring. The M. nivale isolation rate was similar from sites located on greens compared to foregreens, and from greens located at more sunny sites compared to more shadowy located greens. We conclude that this fungus seem to survive from year to year within the same locations on greens and foregreens. A significant correlation was found between mycelial growth rate of M. nivale isolates at 2?C compared to growth at 20?C. At 20?C, a greater variation in growth rate was registered between strains isolated right after snow melt, compared to strains isolated in spring, summer, autumn or prior to snowfall. No clear picture emerged in growth rate differences between groups of M. nivale strains isolated at different time points throughout the year. Significant reduction in mycelial growth rate of M. nivale was registered on agar added low concentrations of all the fungicides tested.The products were: Acanto Prima (cyprodinil, pikoksystrobin), Amistar (azoksystrobin), Amistar duo (azoksystrobin, propikonazol), Baycor (bitertanol), Bumper (propikonazol), Comet (pyraklostrobin), Proline (protiokonazol), Rovral 75WG/Chipco Green 75WG (iprodion), Sportak EW (prokloraz), Stratego 250 EC (propikonazol, trifloksystrobin), Topsin WG (tiofanatmetyl). It was large variation among the fungicides in the effect on fungal growth rate. Sportak, Stratego and Topsin were the most efficient products; 90-100% reduction in mycelial growth rate was registered on agar added 0.1% of the fungicide concentration recommended for disease control on golf greens. Acanto Prima, Bumper, Comet and Stratego were also tested for their effect to reduce snow mould damage on golf greens. Due to severe water damage on the greens the second season, only results from one season of the fungicide field trial could be used. Acanto prima was ranked as the best product, significantly reducing winter injury on average from 21% (in control plots) to 6% in the treated plots.
Forfattere
Lise GrøvaSammendrag
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