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.
2006
Sammendrag
The minirhizotron technique provides the opportunity to perform in situ measurements of fine root dynamics and obtain accurate estimates of fine root production and turnover. The objective of the present work was to determine the fine root longevity and mycorrhization in a Norway spruce chronosequence. The study was carried out on four stands of planted Norway spruce (Picea abies), approximately 10, 30, 60 and 120 years old, during 2001 and 2002. The stands were located at Nordmoen, a plain of sandy deposits in southeast Norway (60o15 N, 11o06 E). For the root turnover study, altogether 60 minirhizotrones were installed and images were processed.Individual fine roots were identified, their mycorrhization assessed, appearance and possible disappearance dated, and growth in length measured. The data set was subjected to a survival analysis, using a Kaplan-Meier product-limit approach. The minirhizotron samples were stratified according to stand age class, and Coxs F-test was used to analyze differences in survival estimates. The analysis may also be extended to consider other covariates such as tree species (spruce, pine or birch), understory vegetation, or soil depth. Typical survival function estimates will be presented, and the influence of stand age on the mycorrhization and the dynamics of the fine roots will be discussed.
Sammendrag
Det er ikke registrert sammendrag
Sammendrag
I debatten om økologisk landbruk og plantevern vert det hevda at bruk av plantevern mot mellom anna insekt og midd vil forstyrre balansen i kulturen. Det er viktig å ha med seg at det å dyrke ein kultur over eit større areal er ei forstyrring i seg sjølv og at resultatet ofte er større angrep på grunn av lett tilgjengeleg mat.
Forfattere
Joha W. Grobbelaar Michael J. Wingfield P. Bloomer Halvor Solheim Brenda D. WingfieldSammendrag
Det er ikke registrert sammendrag
Sammendrag
Det er ikke registrert sammendrag
Forfattere
Leif SundheimSammendrag
Antagonistiske sopper har fått økt betydning som alternativ til kjemiske midler mot plantesjukdommer. Antall markedsførte sopper til bruk i biologisk bekjempelse øker fra år til år. Indudstriell produksjon av uten genetiske endringer og tap av effekt i biokontroll er en utfordring. Regelverket for godkjenning av biologiske preparater varierer fra land til land. Molekylære metoder er nyttige i registrering og markedsføring av sopper til biologisk bekjempelse.
Forfattere
Leif SundheimSammendrag
Globalt øker arealet av genmodifiserte planter (GM planter) med 20 % årlig. Sorter med herbicid- og insekticidresistens har dominert det første tiåret, mens neste generasjon er GM planter med bedre næringsinnhold og som råvare for farmasøytisk og annen industri
Forfattere
Jenny Fäldt Halvor Solheim Bo Långström Anna-Karin Borg-KarlsonSammendrag
To identify chemical resistant markers induced by fungal or mechanical injury, young trees of Scots pine (Pinus sylvestris) were subjected to inoculations of blue stain fungi associated with the pine shoot beetles Tomicus piniperda and T. minor. Among the 20 trees selected for chemical analyses, 16 were divided into four groups: one as control and three were pretreated by wounding only, or by inoculation with either the blue stain fungus Leptographium wingfieldii or Ophiostoma canum.Four wk after pretreatment, all 16 pretreated trees were mass-inoculated with L. wingfieldii. The absolute and relative amounts, as well as the enantiomeric compositions of monoterpene hydrocarbons in the phloem, were determined via a small sample of the phloem before and after the pretreatment and mass inoculation, by using two-dimensional gas chromatography (2D GC) and GC-mass spectrometry (MS).After mass inoculation, the absolute amounts of most of the monoterpenes decreased in the phloem sampled 20 cm from the fungal infection, and were higher in the phloem sampled within the infected reaction zone.The relative amounts of both ()--pinene and ()-limonene increased in phloem samples taken 20 cm above the fungal inoculation in the preinoculated trees compared with phloem sampled from the remaining four control trees. The enantiomeric compositions of -pinene and limonene changed, after fungal growth, at defined distances from the inoculation site: the proportion of the ()-enantiomers was highest in the phloem sampled 20 cm from the fungal inoculation.Four wk after pretreatment, monoterpene production in the phloem at the site of inoculation was more enhanced by L. wingfieldii than by O. canum. However, the different virulence levels of the fungi did not affect the enantiomeric composition of the monoterpenes. The biosynthesis of monoterpene enantiomers is discussed in relation to induced pathogen resistance.
Forfattere
Øyvind Meland Edvardsen Halvor SolheimSammendrag
Det er ikke registrert sammendrag
Forfattere
Trond RafossSammendrag
Det er ikke registrert sammendrag