Publications
NIBIOs employees contribute to several hundred scientific articles and research reports every year. You can browse or search in our collection which contains references and links to these publications as well as other research and dissemination activities. The collection is continously updated with new and historical material.
2005
Authors
Alhaji Jeng Roshan M. Bajracharya Subodh Sharma Bishal K. SitaulaAbstract
No abstract has been registered
Authors
Karl Hilding Thunes R.F. Billings Lawrence R. KirkendallAbstract
De pågående masseangrep av Dendroctonus spp. startet mer eller mindre synkront i alle sentralamerikanske land sent i 1998 og tidlig i 1999; epidemien har hittil ødelagt flere hundre tusen hektar furuskog i Mexico, Belize, Guatemala, Honduras og Nicaragua, og i et mindre omfang El Salvador. Til tross for at landene er små, er naboer og har den samme insektfienden er samarbeid over landegrensene omtrent fraværende. Hele skadebildet og omfanget er også en direkte trusselmot det sterkt truete furu-eik økosystemet i regionen. Et felles regime for forvaltning av furuskogene og deres skadegjørere bør bli utviklet for fremtiden, men koordinert aksjon for å stoppe billene blir forhindret av forskjeller i styrke, kapasitetog mandat hos de forvaltende institusjoner i hvert land. Likevel, omfanget og alvoret i den pågående epidemien har resultert i flere bilaterale og regionale initiativer, og lagt grunnen for formelle, langvarige regionale samarbeidsprogrammer i forvaltningen av denne viktige biologiske ressursen.
Authors
Karin Jacobs Brenda D. Wingfield Halvor Solheim Michael J. WingfieldAbstract
No abstract has been registered
Authors
Bruce Talbot Kjell SuadicaniAbstract
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Authors
Leif Jarle Asheim Lars Olav EikAbstract
Welfare conditions for free ranging animals are in several respects superior to many indoor systems. However, attempts to improve protection of endangered predator species, in particular brown bear (Ursus arctos), wolves (Canis lupus), lynx, wolverine (Gulo gulo), and the golden eagle (Aquila chrysaëtos) during the late 1980s and the 1990s have lead to increasing sheep losses on Norwegian ranges. Predators are causing considerably more pain than slaughtering, a longer time of suffering and sometimes leave surviving animals wounded with scratches or thorn up udders etc. Lambs may be chased away from the mothers. Mitigating measures such as replacing outfield pastures with fenced farmland, sending animals to secure areas or sheep milk production are gradually being introduced. The paper discusses the animal welfare implications induced by the changes currently taking place in the Norwegian sheep industry.
Authors
Gry AlfredsenAbstract
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Abstract
In field experiments, clones of Norway spruce [Picea abies (L.) Karst.] showed different degrees of resistance against pathogenic fungi inoculated into the bark that correlate with differences in polyphenolic parenchyma (PP) cells of the bark. Cells of spruce callus cultures, particularly towards the callus surface, resemble PP cells and this study looks at changes in callus cells during infection and the relative resistance of cultures from clones of low (weak) or high (strong) resistance to fungal infection. Callus cultures, initiated from trees with different resistance, were co-inoculated with Ceratocystis polonica (Siem.) C. Moreau and Heterobasidion annosum (Fr.) Bref. Callus cells from strong clones resemble PP cells of bark tissue from strong clones, having more polyphenolic bodies, while callus cells from weak clones are more similar to PP cells from those clones, which have less extensive phenolic bodies. Callus cultures from trees with weak resistance were more quickly overgrown by both species of pathogenic fungi than cultures from trees with strong resistance. Callus cells of infected cultures showed changes similar to activated PP cells of bark, including enhanced accumulation of polyphenolics. Phenolic bodies were more numerous and more extensive (larger and denser) in callus cells of strong versus weak clones under all conditions. Thus, callus cells may perform similar functions in defense as PP cells in the bark. Callus from trees of varying resistance seem to reflect the relative resistance of the trees from which they are derived, and this study indicates that some mechanisms of resistance can be studied using callus from trees of different resistance.