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.
2011
Forfattere
Christer MagnussonSammendrag
Det er ikke registrert sammendrag
Forfattere
Christer MagnussonSammendrag
Nematodes, commonly known as round worms, are the most common multicellular animals on planet Earth. After 1000 million years of evolution members of the phylum Nematoda have a high bionomic diversity. As habitants of the soil and rhizosphere nematodes are involved en energy fluxes, and affect carbon and nutrient cycles. As plant parasites, either alone or in synergism with other pathogens, nematodes are responsible for plant disease complexes and major crop losses. A growth depression in a field of potato (Solanum tuberosum) cv. Saturna [resistant to pathotype Ro1 of potato cyst nematode (PCN) Globodera rostochiensis], suggestive of potato cyst nematode damage, was detected in Grue, eastern Norway. Analyses of soil samples did not detect PCN, but demonstrated the occurrence of a large number of lesion nematodes Pratylenchus penetrans .Tubers from the depressed part of the field had severe symptoms similar to those caused by the common scab bacterium Streptomyces scabies. Potato yield was reduced by 50% in the affected area of the field. Transect-sampling showed plant growth to be negatively correlated with densities of P. penetrans and suggested a damage threshold of potato to the nematode of 100 specimens per250 g of soil. Common scab (Streptomyces scabies) occurred frequently in the affected area. P. penetrans was present in roots, underground stems, stolons and tubers. Tubers from the depressed part of the field had severe symptoms similar to those caused by the common scab bacterium. In tubers, nematodes were detected inside cross-lesions typical symptoms of common scab, and occurred also in the outermost 0.5 mm tissue associated with such lesions. In pots with sterile sand, micro-tubers of potato cv. Saturna, produced from meristems, were grown in a green-house infected with, P. penetrans, S. scabies, and a combination of P. penetrans and, S. scabies. P. penetrans alone induced tuber lesions similar to those of common scab. Also, the combined inoculation of the bacterium and the nematode seemed to enhance symptom expression. Similar scab symptoms, in connection with lesion nematode infections, have been observed on potato tubers cv. Oleva, which also is relatively tolerant to common scab. Symptomatic tubers cv. Saturna first stored at 4o C for 20 weeks were transferred to pots with sterile sand and grown for 3 months in the green-house. In these cultures P. penetrans was first detected in soil 8 weeks after planting. Examination at harvest of soil, roots, stolons, tubers demonstrated symptoms typical of P. penetrans. Interestingly, P. penetrans survives storage of potatoes, from which new infections may develop. Hence, potato tubers do appear to be an important means for the spread of P. penetrans to new areas. The fact that the symptoms induced by this nematode may be mistaken for symptoms of common scab suggests that the frequency of S. scabies might have been overestimated in regular surveys. Infections by P. penetrans have important implications for scab control. This pertains in particular to recommended maintenance of high soil moisture at and during 4-9 weeks after tuber set. If symptoms are related to nematode infection rather than to the scab bacterium, this recommendation would allow for a rapid build-up of lesion nematodes resulting in a decrease in both yield and marketability of the tubers. Further studies are needed to investigate the extent of this problem.
Forfattere
Halvor Solheim Martti VuorinenSammendrag
During a survey conducted in August 2009 in northern Norway, symptoms typical for red band needle blight (1) were observed in four young Scots pine (Pinus sylvestris) stands. The stands, less than 15 years old, were located in humid sites near rivers in Bardu and Målselv municipalities, Troms County. Many of the oldest needles (2- to 3- years-old) in the lower part of young trees were partially or completely brown, but still attached, and red bands could be observed. Aggregations of conidial stromata were often seen in the red bands. Conidia were hyaline, smooth, thin walled, and filiform, 1.9 to 2.6 μm wide and 12 to 36 μm long....
Forfattere
Helge SjursenSammendrag
I foredraget ble oppbyggingen av ugrasplansjene gjennomgått. I en plansje er alle stadiene i livsyklusen illustrert, fra den første frøplanten til modent frø. Særlig er rotsystemet rikt illustrert. Ved hver deltalj i en plansje er det notert en bokstav, som en kan finne igjen med egne forklaringer i teksthefter. I foredraget ble det framhevet de 10 flerårige artene som ellers ble omtalt under ugrasseminaret: krushøymole, vanlig høymole, byhøymole, lyssiv, knappsiv, hundekjeks, kveke, hestehov, åkertistel og åkerdylle
Forfattere
Helge SjursenSammendrag
Frømelde hører til den biologiske gruppen sommerettårige. Den voksne planten er 20-60 cm høy med svak, greinet pålerot. Stengelen er oftest noe nedliggende, eller opprett, sterkt greinet, firkantet og glatt, ofte noe rødlig. Bladene er stilkete, ovale eller eggformet-elliptiske, med kileformet grunn og helrandet. Blomstene er samlet i knipper i mange, greinete, kvastformete aks i bladhjørnene og i toppen av greiner og stengler. Formeringen og spredningen skjer bare ved frø. Forekommer på dyrket mark, gjødsel- og komposthauger, avfallplasser, veikanter og strandkanter. Opptrer som ugras i hager og i alle slags åkerkulturer, særlig hagebrukskulturer. Mottiltak som for meldestokk.
Forfattere
Helge SjursenSammendrag
Følblom hører til den biologiske gruppen flerårig stedbundne med trevlerot. Den voksne planten er 10-60 cm høy med trevlerot. Planten har hvit melkesaft. Stengelen er oftest gaffelgreinet og bladløs, bortsett fra et lansettformet høyblad i hvert greinhjørne. Bladene er grunnstilt og i rosett, avlange, buktfinnete eller grovt bukttagget. De er mørkegrønne og nesten glatte på oversiden, lysere på undersiden. De gule blomsterkorgene, 2-3 cm i diameter, sitter enslige i toppen av stengel og greiner. De tungeformete kronene er oftest rødaktig på undersiden. Blomsterskaftet er noe fortykket og skjellkledd opp mot korgen. Forekommer i både dyrket og udyrket grasmark, langs veier og jernbaner, og på tomter og ballastplasser. Finnes også i høyfjellet (egen varietet), og vokser på alle slags jordarter, men liker seg aller best på leirjord. Opptrer som ugras først og fremst i eng og beite. Mottiltak: Som for løvetann. Ellers er følblom lett å bekjempe med ugrasmidler som inneholder MCPA.
Forfattere
Igor A. Yakovlev Ari M. Hietala Pierre-Emmanuel Courty Taina Lundell Jan Stenlid Halvor Solheim Carl Gunnar FossdalSammendrag
In forest soils, saprotrophic, necrotrophic and ectomycorrhizal fungi are involved in carbon cycling. Heterobasidion annosum, white rot necrotrophic fungi, is known to decompose wood lignocellulose by secreting a broad range of oxidative enzymes. The genome H. annosum s.l. was sequenced by JGI to a 8.23X coverage and assembled into 39 scaffolds with a total size of 33.7 Mb covering more than 98% of the whole genome. Based on the genome sequence we have characterized gene families coding for enzymes known to participate in conversion of wood lignin: multicopper oxidases (MCOs, 18 genes) as laccases (Lcc), class II peroxidases (8 genes) as manganese peroxidases (MnP), glyoxal oxidases (5 genes, GLOX), quinone-reducing oxidoreductases (19 genes, QOR) and GMC oxidoreductases (12 genes) as aryl alcohol oxidases (AAO). We studied the genomic organisation and phylogeny of these genes as well as their expression using qRT-PCR. Comparative and phylogenetic analyses of genes coding for enzymes involved in wood lignin conversion and decomposition (i.e. lignin-modifying class II peroxidases) reveal differences between white- and brown-rot, necrotrophic and saprotrophic wood-decaying basidiomycetes. Transcript profiling using qRT-PCR revealed that some transcripts were very abundant in lignin-rich media, in cellulose-rich media, in wood or in the free-living mycelium grown liquid culture, suggesting specific functions of these genes, which need to be studied further.
Forfattere
Trond HofsvangSammendrag
Om marihøner som nyttedyr i hager.
Forfattere
Helge SjursenSammendrag
I foredraget ble "hageugras" og "ugrashage" definert, rikt illustrert med bilder.
Forfattere
Trond HofsvangSammendrag
En oversikt over historien til integrert plantevern i Norge. OM LMDs siste handlingsplan for redusert risiko ved bruk av plantevernmidler og målene for integrert plantevern. Om integrert plantevern i EUs direktiv om plantevernmidler fra 2009.