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.
2000
Sammendrag
Vi undersøkte fenologi og kjønnsratio (andel hunner) til 15 arter snylteveps som parasitterer havrebladminerflue i Norge. Studiet gikk over 6 sesonger i byggskiftet i et økologisk drevet felt ved Norges Landbrukshøyskole, og det ble brukt Malaisefeller som innsamlingsmetode (en i åkerkanten og en 60 m inn i byggskiftet). Resultatene tydet på at snyltevepshunnene var mer knyttet til kanten enn hannene og verten sin, og at mange av snyltevepsene vandret ut av åkeren en stund før tresking. De to vanligste snyltevepsartene var Cyrtogaster vulgaris (en puppeparasitt) og Diglyphus begini (en larveparasitt). Førstnevnte hadde en særlig nær tilknytning til kanten, og tidligere studier har vist at denne kan overvintre som voksen i f.eks grastuer i kanten. Hos sistnevnte fant vi en tetthetsavhengig kjønnsratio i fellefangstene: Jo flere individer i fellene, jo lavere andel var hunner
Sammendrag
Det er ikke registrert sammendrag
Sammendrag
The anatomical response of Norway spruce bark polyphenolic parenchyma cells (PP cells) to inoculation with the phytopathogenic fungus Ceratocystis polonica and attack by its bark-beetle vector Ips typographus was examined.Fungal inoculation on the periderm surface had no effect, while inoculation just below the periderm or halfway into the phloem (mid-phloem) generated detectable responses within 3 wk. The responses included increase in PP cell size and in periodic acid - Schiffs staining of PP cell phenolics, wound periderm initiation from PP cells, and cambial zone traumatic resin duct formation. Fungi were not seen in samples 3 wk after subperiderm or mid-phloem inoculation, but were found in some samples 6 and 9 wk after mid-phloem inoculation.In contrast, inoculations into the cambium resulted in partial (3 wk) or complete (6 and 9 wk) fungal colonization and death of tissue in the infected area. This indicates that PP cells have defenses capable of inhibiting fungal growth. Samples taken near bark-beetle galleries had similar anatomical responses as inoculated samples, validating the inoculation approach to studying defense responses in spruce.These results show that PP cells represent not only a constitutive defense system, but are also involved in local and remote inducible defenses against fungal and beetle attack.
Forfattere
Marc H. Schneider J.G. Phillips Stig LandeSammendrag
Filling wood cell cavities or modifying walls with polymer improves mechanical properties and reduces influences of moisture and biodeterioration agents. Properties of untreated wood and wood polymer composites are presented in the paper.
Forfattere
A. SæbøSammendrag
Det er ikke registrert sammendrag
Forfattere
Svein Eilertsen Ivar Schjelderup Stein MathisenSammendrag
Dry matter (DM) production and nutritional quality of plants were recorded on an old meadow before, during and after it was grazed by reindeer (Rangifer tarandus tarandus; 15 reindeer ha-1) in the spring of 1996 and 1997 in northern Norway. Mean herbage harvest after 54 and 50 days of growth including 25 and 24 days of reindeer grazing was 1217±320 kg DM ha-1 in 1996 and 2297±495 kg DM ha-1 in 1997 respectively. On ungrazed old meadow, in contrast (P0.05). Crude protein content (% of DM) was 25 % early in the growing season in both 1996 and 1997. After 54 and 50 days of growth including 25 and 24 days of reindeer grazing, crude protein content was about 17 % of DM both in 1996 and 1997 respectively, compared with about 12 % of DM in ungrazed old meadow both years. In 1997, crude protein content was 13.3 % of DM after 50 days of growth including 7 days of reindeer grazing. The grazed and ungrazed old meadow contained about 20 % (of DM) water-soluble carbohydrates throughout the summer in both years. Mean plant cell wall content in ungrazed plants harvested after about 50 days, was higher (51.5 and 49.1 % of DM; P>0.05), compared to plant cell wall content in grazed meadow (49.0 and 46.4 % of DM) in 1996 and 1997 respectively. In vitro dry matter digestibility (%) of herbage harvest using rumen fluid from domestic ruminants, was about 10 % higher (73.4±0.30 and 75.7±0.28) in samples from grazed meadow compared to ungrazed meadow (66.2±0.93 and 65.4±1.19) in 1996 and 1997. Reindeer grazing old meadow in spring maintains the vegetation at a younger phenological stage during the growing season, when compared to ungrazed meadow. Therefore grazing increased the quality of the herbage, but decreased herbage harvest when exposed to high grazing intensity.
Forfattere
Anne-Grete Buseth BlankenbergSammendrag
Det er ikke registrert sammendrag
Forfattere
E. MangdalSammendrag
Det er ikke registrert sammendrag
Forfattere
J. DavikSammendrag
Det er ikke registrert sammendrag
Forfattere
Jahn DavikSammendrag
En presentasjon av jordbærforedlingen i Planteforsk. Det gis også en kort presentasjon av de mest lovende seleksjonsmaterialet per sommeren 1999.