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
Sammendrag
Det er ikke registrert sammendrag
Forfattere
Ingrid Holtsmark Dimitris Mantzilas Vincent Eijsink May Bente BrurbergSammendrag
The Gram-positive plant pathogen Clavibacter michiganensis subsp. sepedonicus is the causal agent of potato ring rot, a wide-spread disease that causes huge economical losses. One strategy that may aid in gaining control of the disease is the development of agents that specificially inhibit growth of the pathogen. In this work, narrow-spectered antimicrobial substances that are secreted by the closely related tomato pathogen, Clavibacter michiganensis subsp. michiganensis, have been purified and studied. These antimicrobials exert growth inhibitory activity against Clavibacter michiganensis subsp. sepedonicus, and may become useful as control agents in the battle against the potato pathogen. The antimicrobial substances include a 14 kDa bacteriocin, a 2145 Da type B lantibiotic, and a series of non-proteinaceous antibiotics with molecular masses around 800-900 Da, putatively belonging to the tunicamycin family. The lantibiotic peptide, michiganin A, resembles actagardine, which is a type B lantibiotic produced by the actinomycete Actinoplanes liguriae. Both these peptides share traits with mersacidin, a well-known type B lantibiotic, including a conserved residue that is thought to be important for the antimicrobial activity of mersacidin.
Forfattere
Trygve S. Aamlid Oiva NiemelainenSammendrag
Dette foredraget presenterer foreløpige resutater fra et prosjekt med vekstreguleringsmidlet Primo MAXX på golfbaner i Norden. Resultatene indikerer at Primo Maxx bør godkjennes til bruk på golfbaner. Forsøka har vist at vi kan oppnå bedre overvintring og 20% reduksjon i mengde avklipp ved å tilføre Primo Maxx ofte og i små doser, uten at dette går ut over grasets visuelle kvalitet. For store doser vil derimot gi kvalitetsreduksjon. Mer forskning er nødvendig vedrørende optimale doser og tilførselsintervaller til ulike grasarter og på ulike deler av golfbanen.
Sammendrag
Incomplete combustion during vegetation fire can lead to the conversion of plant and soil organic matter (OM) into charcoal. The thermally altered OM is considered to contribute to the stable pool of soil C. Most of the data on thermal alteration of plant material were obtained in the laboratory, whereas fire consequences on ecosystem C storage calls for data collected in natural-fire conditions. The objective of this study was to relate the quality of visually-identified litter charcoal and the temperature recorded during a scrubland prescribed fire. Litter was sampled before and after the fire along a transect in the 30 ha experimental site. Litter-size fractions were analyzed for chemical composition and properties by elementary and isotopic analysis, solid-state 13C nuclear magnetic resonance spectroscopy, differential scanning calorimetry and quantification of oxidation-resistant pyrogenic C. The maximum temperature reached within the litter layer during fire was assessed with thermo-sensitive paints. Our results showed that fire had little effect on bulk litter composition because the fire event induced a large litter fall of both charred and non-charred material, resulting in the impossibility to distinguish new-litter-input and charring processes. As a consequence, the visual identification and separation of burned and unburned material constituted an essential preliminary step for chemical characterization of thermally altered organic matter. Fire temperatures ranged from 370 to 650°C. Charring signifi- cantly increased the litter C concentration by 115 to 142 mg g"1 under the effects of dehydration and aromatization processes occurring above 370°C. A significant correlation appeared between the production of aromatic structures, the decrease of O-alkyl C contribution and the temperature. The relationship between the maximum temperatures reached during the natural fire and the chemical transformation of the litter organic matter appeared highly consistent with previous results obtained under controlled conditions. Heating also led to a significant decrease of the 13C that we interpret as a higher thermal sensitivity of 13C-rich molecules. The elemental composition, NMR and thermal spectra are consistent with the low oxidation-resistant C concentration of this natural charcoal (16±5 % OC), reflecting a low condensation degree compared to graphitic-like model. These findings suggest that leaf-derived charcoal produced during natural vegetation fire may have a lower C storage potential than previously assumed.
Sammendrag
Life on earth depends on water and where running water occurs on earth, there is life. Nevertheless, existing modelling approaches in hydrology almost completely neglect the biological aspects of water flow. We claim that ignoring biological behaviour and interaction in catchment runoff modelling is too restrictive, and that computational theories can be used to formalise behaviour and interaction and model the biological impact on runoff. To demonstrate this, starting with a general classification of catchment behaviour, as documented in runoff data, we will use symbolic dynamics to quantify randomness and complexity in the time series. This approach shows that runoff records from very different catchments show common behaviour. This behaviour can be fitted to a one-parametric curve, stratified into three regions. In this manner, it becomes possible to represent and classify types of interactive behaviour that cannot be generated algorithmically. This suggests that physically based catchment models do not properly represent all types of interactive behaviour, and that signatures of biological interaction are present in runoff data.
Forfattere
Tore SkrøppaSammendrag
Det er ikke registrert sammendrag
Forfattere
Aksel DøvingSammendrag
Det er venta at klimaet skal verte varmare dei neste tiåra. På Vestlandet er det rekna med ein temperaturauke på om lag 1,0 C til 2050 og 2,6 C til 2100, samanlikna med 1980-2000. Data om jordbæravlingane på friland i Valldal ei fjordbygd på Sunnmøre er innsamla for åra 1970-2000. Dei lange tidsrekkene vart brukt for å utvikle regresjonsmodellar som skal forklare verknaden av klimaendring på modningstida for jordbærsorten "Senga Sengana". Middeltemperaturen i månadane mai, juni og juli er avgjerande for modningstida. Dersom starten på haustinga vert definert som den dagen ein kjem opp i 5% av totalavlinga, vert gjennomsnittleg dato for sesongstart 18. juli dei siste 40 åra. Når ein set prognoserte klimaendringar inn i modellane vil det gi ein sesong som er 6 dagar tidlegare i 2050 og 22 dagar tidlegare i 2100 samanlikna med 1970-2000, dersom sortane er lik "Senga Sengana" og dyrkingsteknikken er om lag som no. Det vert rekna med at haustesesongen vert om lag 4 dagar kortare i 2100 enn i 1970-2000.
Sammendrag
Foreløpige resultater effekt av økt CO2, temperatur og skygge om høsten på vekst av kveke, åkertistel og åkerdylle ble presentert.
Sammendrag
Det er ikke registrert sammendrag
Forfattere
Halvor SolheimSammendrag
Climate change may influence in a worse manner for the forests in various ways. Some pathogens may increase their importance and new may arrive. Root and butt rot is the most serious problem in Norway spruce forests. In mean more than every fourth tree is infested when harvested. Dryer summers may give increased frequency of rot caused by Heterobasidion. In addition Armillaria spp may gain change in weather condition both as root rot and in connection with a syndrome together with drought and bark beetles. More unstable winter climate may give increase of Gremmeniella attack on Scots pine. Longer and warmer growth season will give many pathogens better condition. Among those is Ophiostoma novo-ulmi causing Dutch elm disease which is lasting in south eastern Norway at a rather low frequency and the volume of elm is not lower than for 15 years ago. In which way the newly introduced Chalara fraxinea will behave in Norway is uncertain, but a better growth season will probably also influence on the possibility to be spread all over Norway where ash are growing.