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
Forfattere
Nina JohansenSammendrag
Ny og mer miljøvennlig veksthusteknologi vil endre klimaet i veksthusene. Dette vil påvirke balansen mellom skade- og nyttedyr, og kan få betydning for effektiviteten av biologisk og integrert plantevern. Global oppvarming, behov for å beskytte miljøet og høye energipriser gjør at energisparing og -effektivisering i veksthusproduksjonen har topp prioritet. Ny veksthusteknologi inkluderer bl.a. lukkede/delvis lukkede veksthus, veksthus med stor takhøyde, dekkematerialer med ulike spektrale egenskaper, energieffektive lamper med spesielle lysspektre og dynamisk klimastyring der veksthusklimaet får svinge mer i takt med klimaet utendørs. Denne utviklingen vil gi endringer i temperatur, fuktighet, lysforhold og CO2-konsentrasjon i forhold til tradisjonelle dyrkingssystemer. Atferd og biologi hos insekter og midd påvirkes i stor grad av klimaet. Samspillet mellom temperatur og utvikling er godt kjent for mange skade- og nyttedyr, men man vet lite om effekten av de andre. Denne artikkelen gir noen eksempler på det vi vet per i dag om hvordan veksthusklima kan påvirke biologisk og integrert plantevern.
Sammendrag
Sturite et al. (2007) investigated growth and death of the major parts of white clover (Trifolium repens L. cv. "Snowy") plants in pure stand and in mixture with meadow fescue (Festuca pratensis L. cv. "Fure") in a combined plot and root window experiment in Norway (60°42"N, 10º51"E). Leaves, stolons and roots were tagged and their lifespan was monitored in harvested and non-harvested stands during two experimental years. The longevity of leaves and petioles ranged from 21 to 86 d (mean = 59 d). About 60% of the leaves produced during the growing season turned over before the autumn. Of the remaining leaves, 70-80 % were dead or had disappeared by the subsequent spring. The lifespan of sections of the main stolons ranged from 111 to over 677 d (mean = 411 d). In particular, stolon sections close to the parent fragment of undisturbed plants were long lived, while sections towards the terminal bud overwintered more poorly and had a much shorter lifespan. The longevity of roots was from 27 to 621 d (mean = 290 d) and was higher for roots appearing in spring and autumn than in summer. Harvesting significantly reduced the longevity of stolons and caused an increased fragmentation of the white clover plant but did not decrease leaf/petiole or root lifespan.
Sammendrag
Growth, death and N dynamics of leaves, stolons and roots of harvested and unharvested white clover (cv.""Snowy"") were studied in a pot (Sturite et al., 2006) and a combined plot and root window experiment in southeast Norway (Sturite et al., 2007). Leaves of undisturbed plants contained 1.5 g N pot-1 or 6 g N m-2 in late autumn (roughly assuming 4 plants m-2). About 60% of the leaves turned over within the growing season. Thus, in an established, undisturbed white clover stand, leaf turnover would contribute 9 g N m-2 during the growing season. For stolon and root segments tagged during the first growing season, 100% and 91%, respectively, were still present in late autumn. By the end of the second growing season, the corresponding values were 77% and 46%. Thus, dead stolons and roots contributed substantially more to N deposition in the soil in the second than in the first growing season. If taking the turnover of all plant organs into account, the gross N input to the soil-plant system during the two growing seasons would amount to 63 g N m-2. This corresponded to a 2.5-fold increase over the total N in the shoots harvested during the same period.
Sammendrag
Several places in Sogn og Fjordane county, W Norway, old pollarded trees of elm Ulmus glabra stand out as characteristic elements in the cultural landscape. These pollarded trees, which serve as habitats for many groups of organisms and are important key species in the cultural landscape, are threatened due to changes in farming management during the last century. In order to obtain more knowledge about the bryophyte flora on older elm pollards in Sogn og Fjordane county we examined two trees from each of four locations along an east-west gradient, from a strong oceanic climate in coastal areas towards slightly continental conditions further inland. Epiphytic bryophytes were recorded in three different height zones (basal, middle, and top) on the north, east, south and west sides of the trees. We looked for differences in species number (i) between the four locations, (ii) between three height zones (basal, middle and top) of the stems, and (iii) between different expositions (N, S, E and W) of the stems. We found 31 bryophyte species on the eight examined trees. No relation between geographic position and species number was found. There were significantly more species in the basal zones than in the middle zones, while there were no significant differences between the middle zones and top zones, or between the basal zones and top zones. The species number on the northern side exposition was significantly higher than on the eastern and southern sides of the stem.
Forfattere
May-Guri SaethreSammendrag
Urban and peri-urban (UPU) horticulture provides an increasingly important source of income in African countries. A major factor driving the importance of UPU gardening is an increasing marketing opportunity for a growing population of unemployed and unskilled youths in the cities. The potential of UPU gardening is severely undermined by a number of production constraints. Recent field diagnoses in Benin identified severe pest problems and revealed alarming pesticide practices in the UPU areas. Several major pest problems are direct consequences of pesticide abuse that 1) destroys biodiversity required for natural/biological pest control, 2) causes pesticide resistance and pest resurgence and 3) poses personal and environmental hazards. Increasing pesticide use among vegetable producers in UPU gardens in Benin has induced resistance to insecticides in some insect pests. The misuse of pesticides often results in mild to severe human poisonings. Chronic consequences of prolonged exposure to pesticides lack documentation. Additional negative effects are insecticide resistance in insect vectors because of leakage of insecticides to mosquito breeding sites. Insecticide resistance in Anopheles mosquitoes is threatening the success of malaria control programmes. Pesticides which have been banned internationally are commonly used in UPU vegetable production in Africa. Consumer"s consumption of pesticide residues through contaminated products gets little attention. The link between agriculture, environment and health is evident, and climate change contributes to increase already existing challenges.
Forfattere
Igor A. Yakovlev Ari M. Hietala Pierre-Emmanuel Courty Francis Martin Jan Stenlid Halvor Solheim Carl Gunnar FossdalSammendrag
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 of genome sequence we annotated a number of genes for fungal enzymes that are believed to participate in lignin degradation, including: laccases (Lcc18 genes), manganese peroxidases (MnP8 genes) and hydrogen peroxide forming enzymes such as glyoxal oxidases (GLOX5 genes), quinone oxidoreductases (QOR17 genes) and aryl alcohol oxidases (AAO16 genes), which is in concordance with these gene family sizes observed in other sequenced white-rot fungi. We studied the genomic organisation and phylogeny of these genes as well as their expression using NimbleGen arrays and qRT-PCR. Transcript profiling using whole-genome oligo arrays and qRT-PCR revealed that some transcripts were very abundant in lignin-rich media (Lcc5 15, MnP2, GLOX4, QOR2 10, AAO9), in cellulose-rich media (lcc2, 7 16, MnP3 4, GLOX3, QOR4 6, AAO2, 7 10), in wood (Lcc3, MnP4, QOR2, GLOX1, AAO10) or in the free-living mycelium grown liquid culture (Lcc1, 3, 10 13), suggesting specific functions of these genes, which need to be studied further.
Forfattere
Ketil HaarstadSammendrag
A literature review shows that more than 500 organic and metallic compounds have been reported occurring in wetlands, and also that wetlands are suitable for removing pollutants. There are, however, obvious pitfalls for treatment wetlands, the most important being the maintenance of the hydraulic capacity and controlling the detention time. Treatment wetlands should have an adapted design to target specific compounds. Aquatic plants and soils are suitable for wastewater treatment because they have a high capacity of removing nutrients and other substances through uptake, sorption and microbiological degradation. The heavy metals Cd, Cu, Fe, Ni and Pb were found to exceed limit values in water. Also these studies revealed high values of phenol and SO4. No samples showed concentrations in sediments exceeding limit values, but fish samples showed concentrations of Hg exceeding the limit for fish sold in the EU. The main route of heavy metal uptake in aquatic plants was through the roots in the case of emergent and surface floating plants, whereas in submerged plants roots as well as leaves take part in removing heavy metals and nutrients. Submerged rooted plants have potential from water as well as sediments, where as rootless plants extracted metals rapidly only from water. Caution is due about the use of SSF CWs for the treatment of metal-contaminated industrial wastewater as metals are shifted to another environmental compartment and moreover stable redox conditions are required to ensure long-term efficiency. Mercury is one of the most toxic heavy metals and since wetlands have been shown to be a source of methylmercury. Methyl Hg concentrations are typically approximately 15% of Hgt. In wetland water samples, PAH, bisphenol A, BTEX, hydrocarbons including diesel range organics, glycol, DDT, PCB, cyanide, benzene, chlorophenols and formaldehyde were found to exceed limit values. In sediments only PAH and PCB were found exceeding limit values. In the water phase the pesticides found above limit values were atrazine, simazine, terbutylazine, metolachlor, mecoprop, endosulfan, chlorfenvinphos and diuron. There are few listings of these compounds in the commonly used water quality limit values, except for some well-known endocrine disrupters such as nonylphenol, phtalates etc. The performance of extensive household wastewater treatment systems of removing pharmaceuticals and personal care products (PPCPs) are similar to that obtained in conventional activated sludge wastewater treatment plants
Forfattere
Igor A. Yakovlev Carl Gunnar Fossdal Øystein JohnsenSammendrag
The temperature level experienced during zygotic embryogenesis in the conifer Norway spruce effects an epigenetic memory and vital phenological traits in the progeny (Kvaalen & Johnsen, 2008). MicroRNAs (miRNAs) are endogenous small RNAs having large-scale regulatory effects on plant development and could participate in epigenetic regulation of expression in plants. To unravel the possible molecular mechanisms behind this epigenetic phenomenon we prepared two concatemerized small RNA libraries representing smallRNAs expressed in plants from seeds obtained after embryogenesis in cold environment and in a warm environment and made a search of conserved miRNAs found in other plant species. Partial sequencing of the libraries allowed identifying of 199 different small RNAs, with predominant length of 21-nt. Among them were 24 novel candidate miRNAs and 4 conserved. Screening of conserved miRNAs allowed confirming additional 17 miRNAs belonged to 11 miRNA families. Most of the miRNA obtained were related to unknown and “no-hit” genes. The expression of 8 conserved miRNAs (pab-miR156c, 159a, 396a,b, 535, 947, 951 and 858) and 9 predicted miRNAs (miR080, 100, 105, 119, 122, 132, 144a,b and 157) showed significant differences in transcript levels between epigenetically distinct plants. Additionally we confirmed that four selected genes PaLPT4, PaGaMYB, PaMYB10 and PaSPB13 regulated by miRNAs pab-miR100, 858, 159a and 156c, may also be involved in epigenetic memory regulation. Our results suggest that Norway spruce miRNAs are composed of a set of conserved miRNAs and a large proportion of novel non-conserved miRNAs with relatively low expression levels. These findings imply that both kinds of miRNAs might be involved or at least affected by the molecular mechanisms underlying the temperature sensitive epigenetic memory in Norway spruce.
Forfattere
Ingerd Skow Hofgaard Heidi Udnes Aamot Sonja Klemsdal Marikka Jestoi Oleif Elen Guro BrodalSammendrag
During the 1980-1990"s Fusarium avenaceum, Fusarium poae, Fusarium tricinctum and Fusarium culmorum were reported as the most frequently isolated Fusarium species in Norwegian cereals. Recent years studies indicate a shift in the relative prevalence of Fusarium species. In a 6-year period from 2004-2009, researchers at Bioforsk collected about 500 grain samples of spring wheat and oats from farmers" fields in South East Norway to study the effect of environmental factors on development of Fusarium spp. and mycotoxins. Climate data was collected from the nearest weather station, and information on cultivation practice in the respective fields was registered for each grain sample. All grain samples were analyzed for Fusarium-mycotoxin content by LC-MS/MS at the Finnish Food Safety Authority. The DNA content of selected Fusarium species (F. graminearum, F. culmorum, F. avenaceum, F. poae, F. langsethiae/F. sporotrichioides) was determined by quantitative PCR (qPCR). Concentrations of deoxynivalenol (DON) above limit of detection (LOD, 50 µg/kg in oats and 45 µg/kg in spring wheat) were registered in more than 90% of the grain samples. Our data shows a trend towards an increased yearly median value of DON and 3-AcDON together with an increased occurrence of F. graminearum (DNA). In general, F. graminearum was detected at much higher levels than F. culmorum (qPCR). Concentrations of HT-2 and T-2 toxin above LOD were mainly registered in oats where more than 70% of the grain samples had a HT-2 concentration exceeding 80µg/kg. Similarly, the DNA content of F. langsethiae/F. sporotrichioides exceeded 0,1 pg per ng plant DNA in more than 70% of the oat samples, whereas this was only true in less than 5% of the spring wheat samples. As F. sporotrichioides is only sporadically found in Norwegian cereals, these results indicate F. langsethiae as the main HT-2/T-2 producer in Norwegian oats. F. avenaceum (DNA) and enniatins were detected in most grain samples indicating F. avenaceum as still being one of the most prevailing Fusarium species in Norwegian cereals. Moniliformin was detected in several of the grain samples, whereas hardly any samples contained nivalenol or diacetoxyscirpenol. Fusarenon-X, neosolaniol, fumonisin B1 and fumonisin B2 were not detected. Bioforsk has during the last 20-30 years been involved in several projects concerning Fusarium spp. and mycotoxins in Norwegian cereals. Prediction models for plant diseases (including Fusarium spp.) in cereals are today operative within the growing season in the Norwegian web-based disease decision support system, VIPS, administrated by Bioforsk http://www.vips-landbruk.no/. In an ongoing project (2010-2014) we focus on the effect of selected cultivation regimes on survival of Fusarium spp. in plant debris and development of mycotoxins in harvested grains of oats and spring wheat. Results will be used as a basis for further development of disease forecasting models, and for the development of guidelines for cultivation practice in Norway.
Forfattere
Knut Magnar Sandland Peder GjerdrumSammendrag
The objective of the research work has been to investigate whether the quality of dried and planed sawn timber can be improved by sorting logs and planks before the drying process. The research material was selected by randomly choosing 30 butt logs and 30 middle logs in a given diameter class at a sawmill. The logs were sawn in a 4 x log pattern, and one inner plank (near pith) and one outer plank (near bark) were chosen from each log. Various properties were measured on the logs and on the sawn timber before and after drying. The material was then planed, and the quality of the panel boards was registered. Based on the results, different models for sorting the timber before drying to optimise the drying process are proposed. One of them is to separate outer and inner planks. An evident improvement is then expected, both due to possibilities for adjusting the drying process to the moisture content before and after drying, and the possibilities for optimising the drying process in accordance with the requirements of the various wood products. In addition to a separation of inner and outer planks, it is also of interest to separate planks from different types of logs (e.g. butt logs and middle logs) to be able to further optimise the drying process according to the wood properties. The project results also show that the best wood quality for production of panel boards is found in the inner planks from middle logs, mainly due to the knot pattern in the stems.