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.
2010
Sammendrag
In Nordic countries organic farming started as bio-dynamic farms in the 1930s, and still in the 1970s only a small number of farms were organic. Since then the acreage of organic farming has increased and in 2007 Sweden had 222 268 ha (7.9%), Finland 147 557 ha (6.4 %), Denmark 147 482 ha (5.4%), Norway 43 033 ha (4.7%) and Iceland 4 684 ha (0.27%). In northern areas the short vegetation period combined with low temperatures reducing mineralisation causing nutritional deficit may restrict yields. As mineral fertilizers are prohibited in organic farming, plant nutrition and yield depend on proper microbial activity for nutrient cycling. Plant parasitic nematodes (PPN) reduce plant growth, while microbivorous nematodes (MBN) increase nutrient accessibility. Nitrogen fixating legumes, used to improve soil nitrogen levels, may increase densities of PPN to levels causing crop damage. Management of PPN in organic farming relies on knowledge of population dynamics, damaging thresholds and cultural methods like weed control, sanitation, mulching, crop rotation and resistant cultivars. Keeping PPN below damaging levels and supporting beneficial MBN to improve mineralisation would increase yields and improve quality of organics crops in northern areas. Management of MBN is less well understood, but may be of crucial importance for organic farming in northern areas.
Sammendrag
Currently, very little data exist on the exposure of soil biota to engineered nanoparticles (ENPs), in spite of soils being an important potential sink for ENPs. Though, data on exposure are essential to determine whether or not, or to which extent, a hazard constitutes a risk. This knowledge gap is mainly due to difficulties in tracing ENPs in soils where natural nanoparticles are abundant. We used neutron activated ENPs as tracers and examined the exposure (uptake, excretion and internal distribution) of nanoparticles of cobalt (Co NPs 3.9 ± 0.8 nm) and silver (Ag NPs 20.2 ± 2.5 nm) in the earthworm Eisenia fetida, and compared this to soluble cobalt and silver salts. Accumulation patterns were highly different for cobalt and silver. Concentrations of cobalt in worms after 4 weeks exposure reached 88% and 69% of the Co ions and Co NPs concentrations in food, respectively, while corresponding values for Ag ions and Ag NPs were 2.3% and 0.4%. Both Ag NPs and Ag ions in earthworms were excreted rapidly, while only 32% of the accumulated Co ions and Co NPs were excreted within a 4 months depuration period. High accumulation of cobalt was found in blood, and to a lesser extent in the digestive tract. Sequential extraction and centrifugal ultrafiltration provided useful information on metal speciation, dissolution and bioavailability of Co NPs and Ag NPs. Both Ag NPs and Ag ions were strongly bound to soil constituents, whereas Co NPs and Co ions were largely found as water soluble species, in good agreement with the results from the uptake study.
Sammendrag
Det er ikke registrert sammendrag
Forfattere
Hans Geir Eiken Rune Andreassen Alexander Kopatz I WartiainenSammendrag
The use of non-invasive sampling of hairs and scats in wildlife genetics opens the possibility for sampling and analyzing living populations of brown bears (Ursus arctos). The aims of this study have been to develop a quality assured approach for genetic assignment of individual identity of brown bears and to generate a population database that can be used for research, conservation management and forensics. Non-invasive genetic sampling was performed by collection of scats and hairs in the field during the time period from 2004 to 2008. Hair traps were applied to collect hairs from bears in selected geographical areas in 2007 and 2008. Genotypes from 13 STR loci were determined for 232 Norwegian bears. Initial analysis of the entire sample indicated a high level of substructure, and the sample was divided in four geographically different populations consisting of 206 individuals for further validation of the markers. Ten STRs (G1D, G10L, Mu05, Mu09, Mu10, Mu15, Mu23, Mu50, Mu51 and Mu59) conformed to Hardy-Weinberg equilibrium expectations with only minor deviations, while the remaining three STR loci (G1A, Mu26 and G10B) were subjected to further molecular analysis. The average estimate of population substructure for Norwegian bears using 10 STRs (FST) was determined to be 0.1, while the estimate for inbreeding (FIS) was -0.02. Accounting for the FST-value, the average probability of identity (PIave) was 5.67 x 10-10 and the average probability of sibling identity (PIsib) was 1.68 x 10-4. Accreditation in accordance with the international standard ISO17025 was achieved for the described laboratory approach in 2009. We suggest that this approach and STR markers should also be considered to be used for other populations of brown bears in Northern Europe in order to ensure a common quality of the data as well as to facilitate exchange of information in conservation genetics.
Forfattere
Jens Rohloff Per Winge Jahn Davik May Bente Brurberg Keithanne Mockaitis Vladimir Shulaev Stephen K, Randall Atle M. Bones Muath AlsheikhSammendrag
In order to support functional genomics research in octoploid (Fragaria x ananassa Duch.) and diploid (F. vesca) strawberry, a customized Fragaria microarray chip was developed as a joint collaboration between Graminor Breeding Ltd. and NTNU. F. vesca cDNA sequences were provided by The Center for Genomics and Bioinformatics, Indiana University (an assembly of >3 million reads from GS-FLX Titanium - Roche/454 Life Sciences sequencing), and about 59,000 publicly available Fragaria EST sequences were uploaded from NCBI. In addition, ~190 Mb of preliminary draft genome sequences from F. vesca were provided by the Strawberry Genome Sequencing Consortium (courtesy to V. Shulaev). cDNAs used as templates for probe design were validated by BlastN against the F. vesca draft genome excluding cDNAs of microbial origin. Genes not represented in the cDNA collection were identified by screening F. vesca draft genome against protein sequences from Arabidopsis thaliana, Vitis vinifera, Ricinus communis and Populus trichocarpa. Exon sequences from genes not found in the cDNAs were included. In total, 43723 unique 60-mer probes were designed and the Agilent eARRAY tool was used to produce a 4x44k format microarray chip. Fragaria chip applicability and feasibility for transcriptional profiling was investigated using either abiotic (low temperature) or biotic (pathogenic fungi) stress treatment. Microarray data will be subsequently integrated with other omics data to address gene-regulatory networks and biological functions. Cold acclimation experiments were focused on short- and long-term effects in meristematic tissue, and revealed the up-regulation of ~100 cold-responsive genes (transcription factors, dehydrins, enzymes), and transcripts involved in starch breakdown and raffinose biosynthesis. Beside central metabolism, secondary metabolism was also strongly modulated as seen by changes in the expression of flavonoid biosynthesis-related genes. Time-course studies of transcriptional responses in F. vesca accessions showing contrasting resistance toward the pathogen Phytophthora cactorum are in progress, and will be presented in-depth.
Forfattere
Leif Egil Loe Atle Mysterud Erling L. Meisingset Vebjørn Veiberg Barbara ZimmermannSammendrag
Det er ikke registrert sammendrag
Sammendrag
Docks are among the most important perennial weeds in grasslands throughout the world and the need for more effective control methods is especially crucial in organic forage production. To find more effective control methods, field trials over 2 years at 4 Norwegian locations, were carried out mainly as a full-factorial design, including factors expected to reduce docks significantly. (i) Date of grassland establishment: may be important for preventing/decreasing the flush of seedlings from seeds as well as shoots from root fragments.(ii) False seedbed preparation: to decrease soil seed bank. (iii) Use of nurse crop (cover crop) to increase competitiveness against Rumex seedlings. (iv) Cutting the taproot, using a rotary tiller before ploughing, or the "dock-plough" (a skimmer modified to cut roots in the entire furrow width at ca 7 cm depth): as new shoots mostly come from the neck and the upper 5 cm of the taproot. (v) Ploughing depth and skimming: to decrease shoots from root fragments. Weed development was assessed as the number of emerging Rumex seedlings and plants sprouting from root fragments. Results indicated that frequently more plants emerged from seeds than from root fragments. Neither renewing the grassland in summer, nor the use of the rotary tiller or the "dock plough" reduced the number of docks in the renewed grasslands. The use of the false seedbed and nurse crop, at some locations and years, reduced the number of docks in the renewed grasslands. Deep ploughing (24cm) reduced the number of Rumex plants from roots by 65% percent compared to shallow ploughing (16cm). Furthermore, the use of a skimmer reduced the number of docks sprouting from roots by 28%. Among the investigated factors, competitiveness, false seedbed and ploughing depth, as well as ploughing quality, seems to be the most promising factors for reducing the number of docks in renewed grassland.
Forfattere
Chuan Li Heidi Rudi Jihong Liu Clarke Robert Wilson Robert Wilson M Cao Odd Arne RognliSammendrag
Det er ikke registrert sammendrag
Sammendrag
Currently, very little data exist on the exposure of soil biota to engineered nanoparticles (ENPs), in spite of soils being an important potential sink for ENPs. This is mainly due to difficulties in tracing ENPs in soils where natural nanoparticles are abundant. We used neutron activated ENPs as tracers and examined the exposure (uptake, excretion and internal distribution) of nanoparticles of cobalt (Co NPs 3.9 ± 0.8 nm) and silver (Ag NPs 20.2 ± 2.5 nm) in the earthworm Eisenia fetida, and compared this to soluble cobalt and silver salts. Accumulation patterns were highly different for cobalt and silver. Concentrations of cobalt in worms reached 88% and 69% of the Co ions and Co NPs concentrations in food, respectively, while corresponding values for Ag ions and Ag NPs were 2.3% and 0.4%. Both Ag NPs and Ag ions in earthworms were excreted rapidly, while only 32% of the accumulated Co ions and Co NPs were excreted within 4 months. High accumulation of cobalt was found in blood, and to a lesser extent in the digestive tract. Sequential extraction and centrifugal ultrafiltration provided useful information on metal speciation and bioavailability of Co NPs and Ag NPs.
Forfattere
Aksel Døving Arnfinn Nes Simen MyhreneSammendrag
Det er ikke registrert sammendrag