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
Sammendrag
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Sammendrag
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Sammendrag
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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
Axel Schmidt K. Witzel Gazmend Zeneli D. Martin J. Bohlmann Paal Krokene Trygve Krekling Ari M. Hietala Carl Gunnar Fossdal Erik Christiansen Jonathan GershenzonSammendrag
The study of conifer chemical defense has been dominated by investigations of oleoresin and its components. However, the actual function of resin components in plant defense and their mode of action is still uncertain, and the role of other defense compounds is relatively unexplored.We are studying the biochemical and molecular bases of chemical defenses, including terpenes, phenolics and chitinases, in Norway spruce (Picea abies) to learn more about how the accumulation of defense compounds is regulated, with the long-term goal of manipulating defense levels to test their function.Manipulation can be crudely accomplished by treatment with methyl jasmonate, which often mimics the general increases in defenses seen following herbivore or pathogen attack. Such treatment was shown to increase resistance to a fungal associate of bark beetles.To more conclusively test function, isolated genes of defense biosynthetic pathways are being transformed into Norway spruce to produce plants whose defense profiles are altered more precisely.
Sammendrag
When conifers such as Picea abies (Norway spruce) are attacked by insects or pathogens, they often produce increased quantities of terpenoid oleoresin. This response can be mimicked in young P. abies seedlings by treatment with methyl jasmonate. In this study, we determined the effect of methyl jasmonate on the terpenoids and other chemical defenses of mature P. abies, and investigated if this treatment protected trees against attack by the blue-stain fungus Ceratocystis polonica, the most important fungal associate of the bark beetle Ips typographus. Methyl jasmonate treatment induced the formation of traumatic resin ducts in the developing xylem, enhanced resin flow, and stimulated increased accumulation of monoterpenes, sesquiterpenes, and diterpene resin acids. However, almost no significant changes in terpene composition were detected. In addition, no changes in soluble phenolic content were observed. There was a very high variability both among and within clones in the timing and degree of response to methyl jasmonate. These chemical and anatomical changes were correlated with increased resistance to C. polonica, suggesting that terpenoid oleoresin may function in defense against this pathogen.
Sammendrag
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Forfattere
Jorunn BørveSammendrag
Heggeflekk er den mest alvorlege soppsjukdomen på surkirsebær. Angrep kan føra til både omfattande avlingstap i året med infeksjon og i åra etter. Heggeflekk har liknande livvssyklus som epleskurv og difor potensiale til å varslast ved hjelp av automatiserte tenester. Faktorar og kunnskap som er viktige for at varsling av heggeflekk skal kunne etablerast i Noreg er vektlagt i litteraturoversynet.
Sammendrag
Forbrukarane ynskjer plommer dyrka med lite bruk av plantevernmiddel. For å unngå høge tap av plommer under omsetnina av rote,har ein prøvd ut om ekstra sprøyting med kaslium kan vera eit alternativ til bruk av soppmiddel. Ein har samanlikna verknaden av kalsium tidleg i sesongen, seint i sesongen, tilførsel gjennom heile sesongen, soppsprøyta og usprøyta på fruktkvalitet og svinn. Det var ingen signifikante skilnader på kvalitetseigenskapar som refraktometerverdi, syreinnhald, fastleik og farge mellom dei ulike handsamingane. Men frukter som hadde fått kalsium tidleg i sesongen var noko fastare og hadde noko dårlegare fargeutvikling enn andre frukter. Bladgjødsling med kalsium reduserte rotninga etter hausting, men det var ikkje signifikante skilnader mellom tilførsel tidleg eller seint i sesongen.
Forfattere
Guro BrodalSammendrag
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