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.
1994
Sammendrag
Rapporten er en sammenstilling av de viktigste skader og sykdommer som ble registrert på skog i Norge i 1992 og 1993. Skogskadene er dokumentert ved beskrivelse av symptom, årsak og utbredelse. Skogskader som følge av spesielle værforhold har dominert skadebildet i 1992 og 1993. I vestlige kyststrøk førte storm og sjørokk til sterke skader i begge år. En nattefrost i juni 1992 gav sjeldent sterke skader på Østlandet, og tørken på Øst- og Sørlandet samme sommer førte også til ulike skader. Enkelte sopp- og insektangrep har ført til betydelige skader lokalt eller regionalt. Selv om materialets representativitet for skogskadesituasjonen i Norge er begrenset, har de beskrevne skadene høyst sannsynlig vært en del av årsakene til den negative trend som er registrert for kronetetthet og kronefarge i Overvåkingsprogram for skogskader.
1993
Sammendrag
Root dieback disease of Norway spruce (Picea abies) seedlings is a serious problem in Scandinavian forest nurseries. We have chosen spruce seedlings infected with one of the most pathogenic fungi associated with this disease, Pyrhium sp., as an experimental system to study the interaction between root ceUs and fungi. In this experimental system the infection is efficient, resulting in root necrose within 1-2 days, growth retardation and complete wilting within 10 days. Anatomical studies of the infected roots revealed that within 4 days ceU waUs around the inner cortex ceUs were thicker compared to non-infected cells. Staining with methyl red indicated that deposition of lignin or lignin like substances were associated with this thickening of the ceU walls. Neither pectin nor suberin appeared to be deposited in these ceU walls since staining with rhutenium red and Sudan IV were negative.Already1 day after infection several pathogenesis related (PR) proteins with both basic and acidic pIs appeared. Three days after infection the number and amount of PRproteins increased considerably. On the fourth day the num ber of induced proteins were more then 40. The number and also the amount of these proteins remained stable after this day. Two acidic chitinases were present in non-infected roots. Already the first day after infection both of these were strongly induced and were accompanied by four other acidic and two basic chitinases. At day two the activity of the chitinases already mentioned increased and they were accompanied by two chitinases with a more neutral pl. On the third day after infection the chitinase activities stabilized on a steady level This steady state level was maintained to the 10th day. Also 6-1 ,3-glucanases were induced by the infection with Pyrhium sp. While no 6-1 glucanase activity was detected in non-infected roots, one acidic 6-1,3-glucanase was detected the first day after infection. On the second day after infection an additional acidic 6-1,3-glucanase was detected. The number and amount of B-l,3-glucanases, like the chitinases, stabilized on the level of the third day and was maintained unril day 10. These results show that Norway spruce, a gymnosperm, has a response to pathogen infection with many similarities to the angiosperms. They also show that roots respond to the infection in a way similar to the aerial parts.
Sammendrag
Root dieback of Picea abies (L) Karst., Norway spruce, seedlings is a serious problem in Scandinavian forest nurseries. We have chosen spruce seedlings infected with a pathogenic Pythium sp. isolate as an experimental system to study the interaction between the roots of a gymnosperm and a pathogen at the protein level. In this infection system, necroses on the hypocotyl and browning of the upper part of the roots appear within 2 days. Within 10 days the seedlings are completely wilted. Low pH soluble PR-proteins from infected and uninfected roots have been resolved on isoelectrofocusing (IEF) gels. Chitinases, chitosanases and β-1,3-glucanases have been detected enzymatically after IEF. Our results show that more than 30 different pathogenesis-related (PR) proteins accumulated in roots after pathogen infection. PR proteins of low and high isoelectric points appeared within 2 days after infection. In uninfected plants, only one acidic protein was detected. Eight different isoforms of chitinases accumulated after pathogen infection. Two acidic chitinases were constitutively expressed, and one of these strongly accumulated following pathogen infection. Three chitosanase activities were observed in infected plants, while no chitosanase activity was detected in uninfected plants. Also, no β-1,3-glucanase activity was observed in uninfected plants. One acidic β-1,3-glucanase was detected in infected roots after the second day of infection. A second acidic β-1,3-glucanase of relatively higher pI was detected on the fourth day. To our knowledge, this is the first report describing the response of gymnosperm roots to pathogen infection at the protein level. For the first time, we show that PR proteins accumulating after pathogen infection also include chitosanases. It can be concluded from our results that although gymnosperms are evolutionarily very distant from angiosperms, in terms of the production of PR proteins the response of gymnosperm roots resembles that observed in angiosperms.
Forfattere
Isabella BørjaSammendrag
Det er ikke registrert sammendrag
Forfattere
Guro BrodalSammendrag
Det er ikke registrert sammendrag
Vitenskapelig – Fungicide treatment of cereals according to need in the Nordic countries
Guro Brodal
Forfattere
Guro BrodalSammendrag
Det er ikke registrert sammendrag
Forfattere
Halvor SolheimSammendrag
Det er ikke registrert sammendrag
Forfattere
Halvor SolheimSammendrag
Det er ikke registrert sammendrag
Sammendrag
In a field experiment in central Sweden, the vigour of 25-yr-old Scots pines was manipulated by pruning, prior to inoculation with Leptographium wingfieldii and Ophiostoma minus, two blue-stain fungi associated with Tomicus piniperda. Our main purpose was to correlate fungus invasion and host defence reactions with host vigour. Both fungi invaded the inner bark and the sapwood at the points of inoculation. L. wingfieldii caused larger lesions in the bark, but O. minus tended to grow faster in the sapwood. The flow of primary resin was related to tree vigour, whereas carbohydrates present in needles and stem phloem were not. Lesion formation and the content or composition of resin acids in lesions did not differ between fungi or pruning treatments.
Forfattere
Halvor SolheimSammendrag
Det er ikke registrert sammendrag