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.
1993
Forfattere
Dan AamlidSammendrag
Det er ikke registrert sammendrag
Sammendrag
Innhold av nikkel, kopper, samt bly, kadmium, sink, kobolt, jern, mangan, arsen, vanadium og krom ble undersøkt i multer og blåbær fra Jarfjordområdet, et sterkt forurensningsbelastet område i Sør-Varanger, Finnmark, Norge. Forurensningene kommer fra tungmetallindustri på Kola, Russland. Undersøkelsen viste at konsentrasjonene av nikkel og kopper i multer og blåbær var mye høyere i det undersøkte området enn i kontrollområdene. Også konsentrasjonene av arsen var forhøyet. De lokalitetene som hadde de høyeste konsentrasjonene lå i det samme området der det tidligere har vært påvist høye metallkonsentrasjoner i andre planter og i humus. Kvaliteten i bærene kan være av betydning for konsumentene.
Sammendrag
Norwegian forests receive various amounts of air pollutants. Several of them are harmful to trees. The forest health situation is therefore monitored by regular surveys, in accordance with internationally recommended methods. Investigations so far have shown that the deposition of air pollutants is largest in southeastern Norway and in a limited area close to the Russian border, in northeastern Norway.Sulphur and nitrogen compounds are among the main pollutants that may lead to adverse effects. However, their airborne concentrations are not high enough to cause direct injury to trees in Norway, except for northeastern parts being affected by emissions from Russian industries. Indirect injury, by leaching of nutrients from trees and soils, and disturbances of the nutrient balance in various ways, is more likely. Ozone concentrations may reach harmful levels, and may affect vegetation directly, especially in the southern part of Norway.Monitoring is performed in order to reveal whether forest damage occurs from such causes, and if so, where, and whether the amount of damage will change with time. So far the results show that there is no extensive dieback of forests in Norway; the annual death rate of trees is low and appears normal.Based on the international criteria applied, the vitality of the forest appears to be low. Part of the reason for that may be the location of Norwegian forests towards the north, towards mountains, and towards the ocean, where forest growth is limited naturally.However, results indicate that forest conditions in the southern part of the country are affected by air pollution. Most cases of crown discolouration are found in that region, and the number of discoloured (yellow) trees has increased noticeably during the last few years. In the same region crown density has been low, and has been further reduced lately. According to a conservative estimate the average crown density is being reduced by 0.4% (units) annually.Crown density has been shown to be related to tree increment. However, the negative effect of reduced tree vitality is believed to be over-shadowed by the positive effect on growth of nitrogen deposition.Air pollutants are causing various effects in forest ecosystems. It appears that regions in southern Norway receiving large amounts of air pollutants have a high number of acidified lakes containing high concentrations of sulphate and nitrate. In this region the soil is shown to be low in base saturation and leachable phosphate, and high in nitrogen, sulphur and zinc.Those monitored plots showing the highest concentrations of Al and the lowest Ca:Al ratio in their soil water are also located here. The forest in this region receives a more acidic precipitation than elsewhere in Norway, which may contribute to increased leaching from needles. Higher nitrogen deposition is taking place here, causing a heavy cover of epiphytic algae on needles.It is noteworthy that this region contains more low vitality forests (of low crown density and yellowish discolouration) than other regions, and that the negative changes in vitality have been more pronounced than in other regions.More clearly we see that forests in southern, southeastern, and northeastern parts of Norway, next to Russia, are negatively affected. The causal factors may be several, and they may interact in complex processes. The symptoms are not specific, but their regional occurrence seems to indicate a causal relationship with deposition of air pollutants. This indication is now more pronounced than found earlier.
Sammendrag
Det er ikke registrert sammendrag
Sammendrag
Det er ikke registrert sammendrag
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
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Forfattere
Paal KrokeneSammendrag
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Forfattere
Guro BrodalSammendrag
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