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.
2016
Sammendrag
Herbivory by insects and mites on physic nut (Jatropha curcas L.) seedlings was investigated and compared with irrigation in the semi-arid Sahelian Niger, utilizing a randomized complete block design experiment. Three water treatment protocols were applied and the types of damage were recorded. Less than 5% of the seedlings died during the 10-month trial period with sap suckers causing the most damage on the surviving plants. Plants with high production of biomass and leaf cover (foliage) were most strongly positively correlated with irrigation and were also the plants that endured the highest degree of herbivory. The low dieback may indicate that defence mechanisms counteract seedling herbivory and that drought-stressed plants invest more in their defence mechanism system than vital plants.
Forfattere
Yanliang Wang Tore Krogstad Jihong Liu Clarke Moritz Hallama Anne K. Falk Øgaard Susanne Eich-Greatorex Ellen Kandeler Nicholas ClarkeSammendrag
Det er ikke registrert sammendrag
Forfattere
Irene Biancarosa Marit Espe Christian Guido Bruckner Svenja Heesch Nina Sylvia Liland Rune Waagbø Bente Elisabeth Torstensen Erik-Jan LockSammendrag
The Norwegian seaweed industry is expanding and there is a need for accurate estimates of protein content of seaweed species from Norwegian waters. A solid method to calculate protein content is through the sum of the proteomic amino acids; however, it can be expensive and beyond the capacities of many laboratories. The most commonly used method to quantify protein is based on the assessment of crude protein from overall nitrogen content, using the traditional nitrogen-to-protein conversion factor of 6.25. However, this approach can be inaccurate when applied to seaweeds, often resulting in an overestimation of their protein content. Specific nitrogen-to-protein conversion factors, calculated from amino acid composition and total nitrogen, give a more reliable protein quantification in seaweeds. However, no such factors are available for species from Norwegian waters. This study was designed to characterize the amino acid composition of 21 seaweed species from Norwegian waters and use the amino acid data to estimate protein contents of the seaweeds. Crude protein analysis (nitrogen × 6.25) was performed and resulted in overestimation (18–44 %) of the protein content compared to the sum of proteomic amino acids. Specific nitrogen-to-protein conversion factors, calculated for each species, ranged from 3.53 ± 0.1 to 5.13 ± 0.1. This study provides nutritional data on Norwegian seaweeds, covering a relatively wide range of species. Moreover, it is the first study to assess nitrogen-to-protein conversion factors on such species.
Forfattere
Hadush Tsehaye Beyene Abdelhameed Elameen Anne Marte Tronsmo Leif Sundheim Arne Tronsmo Dereje Assefa May Bente BrurbergSammendrag
Amplified fragment length polymorphism (AFLP) was used to study the genetic variation among 80 F. verticillioides isolates from kernels of Ethiopian maize, collected from 20 different maize growing areas in four geographic regions. A total of 213 polymorphic fragments were obtained using six EcoRI/MseI primer combinations. Analysis of the data based on all 213 polymorphic AFLP fragments revealed high level of genetic variation in the F. verticillioides entities in Ethiopia. About 58% of the fragments generated were polymorphic. The genetic similarity among F. verticillioides isolates varied from 46% to 94% with a mean Dice similarity of 73%. Unweighted Pair Group Method with Arithmetic Average (UPGMA) analysis revealed two main groups and four subgroups. The principal coordinate analysis (PCO) also displayed two main groups that agreed with the results of UPGMA analysis, and there was no clear pattern of clustering of isolates according to geographic origin. Analysis of molecular variance: (AMOVA) showed that only 1.5% of the total genetic variation was between geographic regions, while 98.5% was among isolates from the same geographic regions of Ethiopia. Eighty distinct haplotypes were recognized among the 80 isolates analyzed. Hence, breeding efforts should concentrate on quantitative resistance that is effective against all genotypes of the pathogen.
Forfattere
Eivind Vangdal Alena Gibalova Jorunn Børve Iren Knutsen Mojca Korošec Rajko Vidrih Per Gustav Anders LeufvénSammendrag
Aroma is an important quality factor in fruit, and it is important to know the effect of new orchard management practices on fruit aroma. Fruit growers are using more foliar fertilizers to achieve the optimum mineral status in fruit. In this work the effects of adding extra nitrogen, calcium and both nitrogen and calcium to apple trees in the fruit cell division phase were studied. Even though the given nitrogen and calcium did not give significantly higher content of N and Ca in the treated fruits, differences in the contents of some aroma compounds were found. Nitrogen treated trees gave apples with more hexanal, a compound known in unripe ("green, grassy") apples. When both calcium and nitrogen were applied, the negative effect of nitrogen on aroma compounds was less pronounced. The aroma of these fruits was more similar to the controls. Using multivariate statistical analyses, the grouping of the different treatments during storage was confirmed. Foliar fertilization with nitrogen and calcium during the cell division phase had a significant effect on the amount of aroma compounds in apples at harvest and during storage.
Forfattere
Gudbrand Lien Subal Chandra Kumbhakar J. Brian HardakerSammendrag
Empirical studies have often shown wide differences in productivity among firms. Although several studies have sought to identify factors causing such differences, only a few studies have examined the effects of risk and risk aversion on productivity. In this study, using Norwegian dairy farming data for 2009, we examined the effects of different aspects of risk on productivity. We used a range of variables to construct indices of risk taking, risk perception and risk management. These indices were then included as arguments in an input distance function which represents the production technology. Our results show that these risk indices did affect productivity. Regional differences in productivity, though small, were also found to exist, suggesting that unobserved edaphic factors that differ between regions also affected productivity.
Forfattere
Aruppillai Suthaparan Knut Asbjørn Solhaug Nils Bjugstad Hans Ragnar Gislerød David M. Gadoury Arne StensvandSammendrag
Disease-suppressive effects of nighttime applications of ultraviolet-B (UV-B) were investigated at two irradiance levels (1.6 or 0.8 W/m2) in strawberry and rosemary plants inoculated with Podosphaera aphanis or Golovinomyces biocellatus, respectively. Plants were exposed to each irradiance level every third night for either 9 or 18 min, every night for either 3 or 6 min, or three times every night for either 1 or 2 min. Thus, over time, all plants received the same cumulative dose of UV-B, and severity of powdery mildew was reduced by 90 to 99% compared with untreated controls in both crops. Use of polished aluminum lamp reflectors and UV-B reflective surfaces on greenhouse benches significantly increased treatment efficacy. An automated apparatus consisting of an adjustable boom with directed airflow was used to move UV-B lamps over greenhouse benches at 25 or 50 cm/min. Directed airflow moved leaves on the subtending plants to better expose upper and lower surfaces to UV-B but directed airflow actually decreased the efficacy of UV-B treatments, possibly by dispersing conidia from lesions before they were exposed to a lethal dose of UV-B. Results indicate broad applicability of nighttime applications of UV-B to suppress powdery mildews, and that cumulative UV-B dose is an overriding factor determining efficacy. Finally, enhanced suppression on shaded or obscured tissues is more likely to be affected by reflective bench surfaces than through attempts to physically manipulate the foliage.
Sammendrag
Introduced tree species represent a substantial component of urban forests in cities all over the world. Yet there is controversy about the further use of introduced tree species. Many practice orientated publications,research papers and governmental websites in the fields of urban planning, urban forestry, and urban ecology argue for planting native species and avoiding introduced species. Such arguments for native-only species selection are also touted by environmental groups and the media. Consequently the debate has sometimes spiralled away from a sensible and rational platform where invasion risks and biodiversity loss are discussed, to a groundless and unreasonable argument where exotic species are generally considered incapable of providing ecosystem services. From a European perspective, we here aim to curate a set of necessary considerations for current and future discussions on native and non-native plant material in sustainable urban development. Using examples from Northern and Central Europe we illustrate that in some regions the catalogue of native tree species may be too limited to fulfil ecosystem services and resilience in harsh urban environments. A main message from our line of arguments is that we cannot afford to generally exclude non-native tree species from urban greening. If “native-only” approaches become incorporated in regional, national or international policy documents or legislation there is a risk that urban ecosystem resilience will be compromised, particularly in regions with extreme environmental conditions. Since both invasion risks and sizes of native species pools vary conspicuously at regional to continental scales we also argue to adapt urban policies on using non-native trees to regional contexts.
Sammendrag
Nonylphenols (NP) are a group of alkylphenols, formed upon degradation of nonylphenol ethoxylates such as nonylphenol monoethoxylate (NP1EO) or nonylphenol diethoxylate (NP2EO), which have been broadly used as non-ionic surfactants. Both NP and their ethoxylates are often present in the sewage, despite being banned and substituted by less toxic alcohol ethoxylates in many countries. There is a number of degradation studies of nonylphenol in the soil environment, but there is a lack of understanding on how plants and soil organisms such as earthworms can affect the degradation. In our study, we investigated the degradation of 4-nonylphenol (4-NP) in a mineral field soil in the presence of barley (Hordeum vulgare) and earthworms (Aporrectodea caliginosa). Soil was spiked with 4-NP at a concentration of 12.5 mg kg-1 d.w. soil. Results showed that the degradation of 4-NP in soil was rapid during the 28 days after spiking, with remaining concentration of 0.397 mg kg-1 d.w. soil on day 28. Degradation was much slower between days 28 and 120, with a remaining concentration of 0.214 mg kg-1 d.w. soil on day 120. No significant difference in the degradation of 4-NP in the presence of either plants or worms was observed, but sampling after 28 days of exposure revealed transfer of 4-NP to worms (worm tissue concentration = 0.79 μg g-1), which increased with time (1.66 μg g-1 after 120 d). The calculated transfer factor after 28 (TF28) and 120 days (TF120) was 0.07 and 0.13 respectively. No toxicity or accumulation in plants was observed at the concentration tested herein. Concentration of 4-NP in the rhizosphere was not statistically different from that in the bulk soil.
Forfattere
Priit Tammeorg Ana Catarina Bastos Simon Jeffery Frédéric Rees Jürgen Kern Ellen R. Graber Maurizio Ventura Mark Kibblewhite António Amaro Alice Budai Cláudia M.d.S. Cordovil Xavier Domene Ciro Gardi Gabriel Gascó Jan Horak Claudia Kammann Elena Kondrlova David Laird Susana Loureiro Martinho A.S. Martins Pietro Panzacchi Munoo Prasad Marija Prodana Aline Peregrina Puga Greet Ruysschaert Lidia Sas-Paszt Flávio C. Silva Wenceslau Geraldes Teixeira Giustino Tonon Gemini Delle Vedove Costanza Zavalloni Bruno Glaser Frank G. A. VerheijenSammendrag
Key priorities in biochar research for future guidance of sustainable policy development have been identified by expert assessment within the COST Action TD1107. The current level of scientific understanding (LOSU) regarding the consequences of biochar application to soil were explored. Five broad thematic areas of biochar research were addressed: soil biodiversity and ecotoxicology, soil organic matter and greenhouse gas (GHG) emissions, soil physical properties, nutrient cycles and crop production, and soil remediation. The highest future research priorities regarding biochar’s effects in soils were: functional redundancy within soil microbial communities, bioavailability of biochar’s contaminants to soil biota, soil organic matter stability, GHG emissions, soil formation, soil hydrology, nutrient cycling due to microbial priming as well as altered rhizosphere ecology, and soil pH buffering capacity. Methodological and other constraints to achieve the required LOSU are discussed and options for efficient progress of biochar research and sustainable application to soil are presented.