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.
2004
Forfattere
H Schmidt A. Adler Arne Holst-Jensen Sonja Klemsdal C.M. Kullnig-Gradinger Antonio Logrieco C.P. Kibecek Robert L. Mach Rudi F. Vogel Helga I. Nirenberg Ulf Thrane Mona Torp Tapani Yli-Mattila Ludwig NiessenSammendrag
Det er ikke registrert sammendrag
Forfattere
Alhaji Jeng Trond Knapp Haraldsen Nils Vagstad Arne Grønlund Steinar TveitnesSammendrag
Nitrogen, fertilizer, meal
Sammendrag
The anatomical defense responses in stems of Norway spruce (Picea abies) clones of different resistance to pathogenic fungi were characterized over time and distance from small mechanical wounds or wounds inoculated with the root rot fungus Heterobasidion annosum. Common responses for both treatments included division of ray parenchyma and other cells in the cambial zone, accumulation of phenolic inclusions in ray parenchyma cells, activation of phloem parenchyma (PP) cells, and formation of traumatic resin ducts (TDs) in the xylem. TD formation occurred synchronously from a tangential layer of cells, or symplasmic domain, within the zone of xylem mother cells. TD induction is triggered by a signal, which propagates a developmental wave in the axial direction at about 2.5cm per day. TDs are formed at least 30cm above single inoculations within 16–36days after inoculation. The size and number of TDs is attenuated further away from the inoculation site, indicating a dose-dependent activity leading to TD development. Compared to sterile wounding, fungal inoculation gave rise to more and larger TDs in all clones, and multiple rows of TDs in weak clones. Fungal inoculation also induced the formation of more new PP cells, increasing the number of PP cells in the phloem in the year of inoculation up to 100%. TD and PP cell formation was greater in susceptible compared to resistant clones and after fungal versus sterile inoculation. Potential mechanisms responsible for this variable response are discussed.
Forfattere
Halvor B. Gjærum Kåre Arnstein Lye Halvor SolheimSammendrag
Det er ikke registrert sammendrag
Forfattere
Nina Elisabeth Nagy Carl Gunnar Fossdal Paal Krokene Trygve Krekling Anders Lönneberg Anders Lønneborg Halvor SolheimSammendrag
Polyphenolic parenchyma cells (PP cells) in Norway spruce (Picea abies (L.) Karst.) stem phloem play important roles in constitutive and inducible defenses. To determine whether anatomical and molecular changes in PP cells are correlated with tree resistance, we infected two Norway spruce clones with the pathogenic fungus Ceratocystis polonica (Siem.) C. Moreau. The fungus induced significantly different lesion lengths in the two clones, indicating that one clone was more resistant to the fungus (short lesions) than the other (long lesions). After infection, the cross-sectional area of PP cells and their vacuolar polyphenol bodies increased in the three most recent annual rings of PP cells in both clones. The more resistant clone had larger PP cells with denser polyphenol bodies than the less resistant clone, whereas the less resistant clone accumulated relatively more polyphenols after infection. Compared with the less resistant clone, the more resistant clone contained higher starch concentrations before infection that were reduced more quickly after infection before returning to original values. Low transcript levels of chalcone synthase were detected in uninfected tissues of both clones, but the levels increased dramatically after infection. Transcript levels were higher and peaked 6 days earlier in the more resistant clone than in the less resistant clone. The activity of at least one highly basic peroxidase isoform was greatly enhanced after infection, and this increase occurred earlier in the more resistant clone.
Forfattere
Matthias Koesling Martha Ebbesvik Gudbrand Lien Ola Flaten Paul Steinar Valle Halvard ArntzenSammendrag
This study presents empirical insight into organic and conventional cash crop farmers' perceptions of risk and risk management strategies, and identifies socio-economic variables linked to these perceptions. The data originate from a questionnaire survey of farmers in Norway. The results indicate that organic farmers perceived themselves to be less risk aversethan conventional farmers. For both groups, crop prices and yield variability were the two top rated sources of risk, followed by institutional risks. The two groups evaluated risk management strategies quite similarly; favoured strategies weregood liquidity and to prevent and reduce crop diseases and pests. The farmers' evaluation of sources of risk and choice of risk strategies depended onvarious socio-economic variables. The importance of institutional risks implies that policy makers should be cautious about changing policy capriciously and they should consider strategic policy initiatives that give farmers more long-term reliability.
Forfattere
Vidar Selås Olav Hogstad Sverre Kobro Trond RafossSammendrag
Cyclic outbreaks of forest moth pest species have long remained a puzzle for foresters and ecologists. This paper presents time-series exhibiting a strong negative relationship between sunspot numbers and population indices of autumnal and winter moths, both in a mountain birch forest in central Norway and in a mixed lowland forest in southern Norway. In the latter area, also the population level of a moth species feeding entirely on lichens was negatively related to sunspot numbers. Low sunspot activity leads to a thinner ozone layer and thus higher surface ultraviolet (UV)-B radiation. As winter moth larvae prefer leaves subjected to enhanced UV-B radiation, we suggest that the causal relationship between sunspots and moths is that the metabolic costs of producing UV-B-protective pigments during periods of low sunspot activity reduce trees" and lichens" resistance to herbivores, and thus increase the survival of moth larvae. Higher peak densities of moth cycles in mountain forests could be explained by the general higher UV-B radiation at higher altitudes.
Sammendrag
Det er ikke registrert sammendrag
Fagartikkel – Norske grassorter på norske golfbaner?
Trygve S. Aamlid, Bjørn Molteberg, Arne Tronsmo
Sammendrag
Nye forsøk viser at norske sorter av engkvein, krypkvein og rødsvingel jamt over har grovere blad og mindre skuddtetthet, men langt bedre overvintringsevne enn importerte sorter av samme art. De norske sortene har derfor en naturlig plass i frøblandinger til golfbaner i høgereliggende områder. Til tross for lav prioritert og flere avbrudd i foredlingsarbeidet har det kommet en del norske grøntanleggssorter på markedet. Jamt over viser disse bedre overvintringsevne enn de importerte sortene. Golfbaner med årvisse overvintringsskader vil derfor kunne spare store beløp på å ta de norske sortene med i frøblandingene. Samtidig vil vi sterkt beklage at Graminor AS har valgt å avslutte all norsk foredling av gras til grøntanlegg.
Sammendrag
Genene utgjør en del av gensekvensen på kromosomene, og flere organismer har de siste årene fått sine genom ferdig sekvensert. Gensekvensene ligger lagret i databaser som er tilgjengelig for forskere over hele verden, og arbeidet med å forstå hva alle genene gjør og hvordan de er regulert er allerede i gang. Funksjonell genomforskning kalles dette arbeidet, og norske forskere og norsk industri er med for fullt. Med støtte fra Stortinget og Norges Forskningsråd ble det i fjor opprettet et eget program for funksjonell genomforskning (FUGE). Foreløpig er det bevilget 200 millioner kroner til dette programmet, men etter planen skal det trappes opp til 300 millioner kroner per år over en ti-årsperiode. Gjennom et samarbeid mellom NTNU, UiO og NLH har norske planteforskere fått 30 millioner til studier av det lille, uanselige ugresset vårskrinneblom.