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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.

2023

Sammendrag

Tap av organisk materiale, jordpakking og erosjon truer jordhelsa på kornareal. Problemer med dette vil antagelig øke i et våtere klima og medføre store kostnader for både gårdbrukere og samfunn. Fremover må vi passe på å stabilisere erosjonsutsatt jordoverflate og sikre en god infiltrasjon av nedbør. På kornareal er lav årlig tilførsel av karbon en begrensende faktor for aggregering og stabilisering, men dette kan forbedres ved å beholde halmen på jordet eller bruke en tilpasset fangvekststrategi. En bør trolig skjevfordele tilført organisk materiale mer mot jordas overflate og dermed stimulere mikrobiell aktivitet i jordas toppsjikt. Da må en minimere jordarbeidingsintensiteten. Slik redusert jordarbeiding fører også til utvikling av et kontinuerlig poresystem nedover i profilet som kan øke infiltrasjonen etter kraftige nedbørsepisoder og dermed bidra til å dempe flomtopper. Store mengder plantemateriale ved jordoverflaten gir imidlertid også noen utfordringer. Det trengs økt kunnskap om ugrasbekjempelse, spesielt i et scenario der glyfosat blir forbudt. Minimal jordarbeiding med planterester på jordoverflaten kan også øke angrep av sopp. Integrerte plantevernstrategier bør identifisere arter og sorter av matplanter og fangvekster som kan bidra til å begrense forekomst av patogener i jord og halmrester. Bedre jordhelse på kornareal er en tverrfaglig utfordring og krever en varig endring av dagens dyrkingspraksis.

Sammendrag

Crown rot, caused by Phytophthora cactorum, is a devastating disease of strawberry. While most commercial octoploid strawberry cultivars (Fragaria × ananassa Duch) are generally susceptible, the diploid species Fragaria vesca is a potential source of resistance genes to P. cactorum. We previously reported several F. vesca genotypes with varying degrees of resistance to P. cactorum. To gain insights into the strawberry defence mechanisms, comparative transcriptome profiles of two resistant genotypes (NCGR1603 and Bukammen) and a susceptible genotype (NCGR1218) of F. vesca were analysed by RNA-Seq after wounding and subsequent inoculation with P. cactorum. Differential gene expression analysis identified several defence-related genes that are highly expressed in the resistant genotypes relative to the susceptible genotype in response to P. cactorum after wounding. These included putative disease resistance (R) genes encoding receptor-like proteins, receptor-like kinases, nucleotide-binding sites, leucine-rich repeat proteins, RPW8-type disease resistance proteins, and ‘pathogenesis-related protein 1’. Seven of these R-genes were expressed only in the resistant genotypes and not in the susceptible genotype, and these appeared to be present only in the genomes of the resistant genotypes, as confirmed by PCR analysis. We previously reported a single major gene locus RPc-1 (Resistance to Phytophthora cactorum 1) in F. vesca that contributed resistance to P. cactorum. Here, we report that 4–5% of the genes (35–38 of ca 800 genes) in the RPc-1 locus are differentially expressed in the resistant genotypes compared to the susceptible genotype after inoculation with P. cactorum. In particular, we identified three defence-related genes encoding wall-associated receptor-like kinase 3, receptor-like protein 12, and non-specific lipid-transfer protein 1-like that were highly expressed in the resistant genotypes compared to the susceptible one. The present study reports several novel candidate disease resistance genes that warrant further investigation for their role in plant defence against P. cactorum.

Til dokument

Sammendrag

The effects of tree pollen on precipitation chemistry are not fully understood and this can lead to misinterpretations of element deposition in European forests. We investigated the relationship between forest throughfall (TF) element fluxes and the Seasonal Pollen Integral (SPIn) using linear mixed-effects modelling (LME). TF was measured in 1990–2018 during the main pollen season (MPS, arbitrary two months) in 61 managed, mostly pure, even-aged Fagus, Quercus, Pinus, and Picea stands which are part of the ICP Forests Level II network. The SPIn for the dominant tree genus was observed at 56 aerobiological monitoring stations in nearby cities. The net contribution of pollen was estimated as the TF flux in the MPS minus the fluxes in the preceding and succeeding months. In stands of Fagus and Picea, two genera that do not form large amounts of flowers every year, TF fluxes of potassium (K+), ammonium-nitrogen (NH4+-N), dissolved organic carbon (DOC), and dissolved organic nitrogen (DON) showed a positive relationship with SPIn. However- for Fagus- a negative relationship was found between TF nitrate-nitrogen (NO3−-N) fluxes and SPIn. For Quercus and Pinus, two genera producing many flowers each year, SPIn displayed limited variability and no clear association with TF element fluxes. Overall, pollen contributed on average 4.1–10.6% of the annual TF fluxes of K+ > DOC > DON > NH4+-N with the highest contribution in Quercus > Fagus > Pinus > Picea stands. Tree pollen appears to affect TF inorganic nitrogen fluxes both qualitatively and quantitatively, acting as a source of NH4+-N and a sink of NO3−-N. Pollen appears to play a more complex role in nutrient cycling than previously thought.