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
The effects of different production systems on sensory profile and fatty acid composition were examined in a study performed in Northern Norway (65o50"N, 12o28"E) in 2008. One-hundred and fifty Norwegian White Sheep lambs grazed on the same semi-natural pasture with their dams for three months or more. The effect of pre-slaughter fattening on meat quality was compared using a control group of lambs slaughtered directly from the pasture. Four pre-slaughter treatments were established: weaning and indoor-feeding on concentrate and grass silage for either 24 or 44 days before slaughtering (Conc24, Conc44), weaning and grazing on ryegrass (Lolium multiflorum) pasture for the same periods (Rye24, Rye44). Loin samples of M. Longissimus dorsi including the subcutaneous fat over the muscle from fifteen carcasses from each treatment were analysed for sensory attributes and fatty acid composition. A lower intensity of acid taste was observed in meat from lambs in treatment Conc44 compared with meat from lambs in the control treatment. A higher content of the fatty acids C16:0, C18:1n-9 and C18:2n-6 and the n-6/n-3 ratio was related to meat from lambs fed concentrate, while a higher of the fatty acids C18:0, C18:1t-11 and C18:3n-3 was found in meat from grazing lambs.
Sammendrag
The Skuterud catchment is a small artificially drained agricultural catchment, located in south eastern Norway. The total area of the catchment is 4.5 km2 of which agriculture covers 2.7 km2, forest 1.3 km2 while the rest is occupied by urban area. The main agricultural crops are wheat, barley and oat. The climate is cold temperate continental or subarctic with a winter season, lasting from November -March and characterized by periods with below-zero temperatures and a varying degree of snow cover, interchanged with thaw periods combined with precipitation and runoff. In Norway, melt water, causing surface runoff, is one of the most serious reasons for erosion, in addition to near-saturated soil moisture conditions after longer periods with rainfall during the autumn. Climate change can potentially lead to an increase in the number of freeze/thaw cycles which in addition to the predicted increase in precipitation during the period after the growing season from September - April, might lead to an increase in both the amount of runoff and its intensity, with subsequent adverse effects on erosion and nutrient loss. Models are indispensable tools in the prediction of climate change effects on runoff generation. In this respect, the Drainmod model has been tested on the Skuterud catchment concerning its ability to predict runoff from an artificially drained agricultural catchment under prevailing winter conditions. The results are presented in this paper. If proven successful, the model can be used to predict the long term hydrologic impacts of climate change for the Norwegian conditions
Forfattere
Christer MagnussonSammendrag
S.radicicola is a parasite of barley and grasses like Poa annua and P.pratensis. The life cycle of a Norwegian population of S.radicicola (Poa-race) is studied in the laboratory by inoculating newly germinated P.annua (cv. Leif) with 140 juveniles from field collected galls and keeping the plants at 25˚C and 16 hrs light period. Juvenile stages are separated based on genital development. The first stage (J1) has 1 cell, while the following stages J2, J3 and J4 has 2, 3 and 4 (or more) cells in their genital primordia. J1 (L = 310-350μm) moults in the egg and J2 (L = 330-400μm) is the hatching stage. Nematodes emigrating from field collected galls were all J3:s (L = 360-430μm), and moulted outside the gall to J4 (L = 210-500μm). The first stage to appear in newly formed galls is large J4 (L=500-870 μm), which moults within 5 days to adult (L=820-1980 μm). Egg-laying starts within 13 days and eggs hatch after 22 days. Juvenile development in eggs starts at 5˚C, and 640 degree days are required for completing one generation corresponding to about 30 days at 25˚C. This means that in Norway S.radicicola may have up to 3 generations per year. The fact that J3 exit the galls and the large J4 is the first stage present in newly formed galls makes us speculate that the induction of gall formation occurs from outside by pre-infective J4, which later infects and develop inside the gall. Key Words: Root gall nematode, Subanguina radicicola, Poa annua, life cycle, Norway
Forfattere
Christer MagnussonSammendrag
The recent spread of pinewood nematode (PWN) Bursaphelenchus xylophilus in Europe is a concern to Nordic countries. Since PWN may exist in trees free of symptoms its distribution becomes unclear. Commodities like pulpwood, particle wood (PW) and wood packaging material (WPM) could have hidden infections. Pulpwood offers obvious risks of transmission due to a possible presence of both PWN and its vectors (Monochamus spp.). Generally, PW is considered to pose a low theoretical risk due to absence of vectors, and WPM no risk if heat treated. Transmission of PWN from infested wood to trees has been demonstrated, and a recurrent use of PW on sports tracks may during one forest cycle result in transmission. PWN can survive for long periods in wood, and reported limited heat treatment capacities indicate that infested WPM already may circulate within the EU. In the Nordic region, pallet wood is a popular fuel and is stored at summer houses where direct contact with trees could cause transmission. In Nordic locations establishment of PWN is expected to cause damage only in hot summers. Even in a warmer climate the damage at least in a 50 yrs perspective is expected to be small, but costs of nematode control will be very high. In a short perspective effects on Nordic exports are small, but in a longer perspective new outbreaks of pine wilt disease in Europe could change export markets. Key Words: Pinewood nematode, Europe, trade risks, Nordic region
Sammendrag
Bipolaris sorokinana (teleomorph Cochliobolus sativus) is a widespread pathogen of cereals and many grasses. It can infect seeds, roots and leaves, causing seedling blight, common root rot, foot rot and spot blotch. Inoculum of B. sorokiniana may be seed-borne or arise from infected plant debris in the field and from conidia in the soil. Recent years the pathogen has occurred at high frequencies in seed lots of barley in Norway, especially in the cvs Edel and Annabell. A large proportion of the seed lots tested since 2004 were infected and the average infection frequencies were rather high. In order to evaluate the importance of the seed-borne inoculum in barley and to test the effect of seed treatment fungicides against the pathogen, field, greenhouse and laboratory experiments have been carried out with heavily infected barley seed. The infection level was reduced and plant weight, plant height, field emergence and yields were significantly increased by chemical treatment. The best effect was seen with an imazalil+flutriafol compound which increased the yield by approximately 35 % compared to untreated. A healthy untreated seed lot of the same cultivar included in one of the experiments showed approximately the same level of emergence and yield as the best fungicide treatment of a heavily infected seed lot. The investigations demonstrate that the use of healthy seed, or seed treated with an effective fungicide, is important to reduce the yield losses from B. sorokiniana.
Sammendrag
Bipolaris sorokinana (teleomorph Cochliobolus sativus) is a widespread pathogen of cereals and many grasses. It can infect seeds, roots and leaves, causing seedling blight, common root rot, foot rot and spot blotch. Inoculum of B. sorokiniana may be seed-borne or arise from infected plant debris in the field and from conidia in the soil. Recent years the pathogen has occurred at high frequencies in seed lots of barley in Norway, especially in the cvs Edel and Annabell. A large proportion of the seed lots tested since 2004 were infected and the average infection frequencies were rather high. In order to evaluate the importance of the seed-borne inoculum in barley and to test the effect of seed treatment fungicides against the pathogen, field, greenhouse and laboratory experiments have been carried out with heavily infected barley seed. The infection level was reduced and plant weight, plant height, field emergence and yields were significantly increased by chemical treatment. The best effect was seen with an imazalil+flutriafol compound which increased the yield by approximately 35 % compared to untreated. A healthy untreated seed lot of the same cultivar included in one of the experiments showed approximately the same level of emergence and yield as the best fungicide treatment of a heavily infected seed lot. The investigations demonstrate that the use of healthy seed, or seed treated with an effective fungicide, is important to reduce the yield losses from B. sorokiniana.
Forfattere
Christer MagnussonSammendrag
The spread of the pinewood nematode (PWN) Bursaphelenchus xylophilus in Europe is a threat to 36 million ha Nordic coniferous forests. In spite of a strict phytosanitary regulation of wood imports, the volumes and an unclear distribution of PWN could result in an introduction into the Nordic region. In the present climate expression of pine wilt disease is expected only in hot summers. Hence, the detection of PWN in the Nordic area is likely to remain unnoticed for a considerable period of time. In Fennoscandia more than 9000 samples have been analyzed from risk areas and risk commodities. The focus often has been on the breeding substrate of the vector insects in the genus Monochamus. A recent study on a simulated introduction in Norway (Økland et al in print) indicates that 14 years may elapse before detection by the present level of 400 samples annually. It was demonstrated that an earlier detection of PWN provided by an annual sample volume of 10 000 samples would still not be sufficient for successful eradication of PWN by 3 km radius clear-cuts. So, large sampling volumes and strict import regulations for PWN are highly important for the Nordic area. Økland, B.O. Skarpaas, M. Schroeder, C. Magnusson, Å. Lindelöw & K. Thunes 2010. Is Eradication of the Pinewood Nematode (Bursaphelenchus xylophilus) Likely? An Evaluation of Current Contingency Plans. Risk Analysis in print Key Words: Pinewood nematode, Nordic area, sampling, eradication, regulation
Forfattere
Marcel Van Oijen Ad Schapendonk Mats HøglindSammendrag
Background and Aims The carbon balance of vegetation is dominated by the two large fluxes of photosynthesis (P) and respiration (R). Mechanistic models have attempted to simulate the two fluxes separately, each with their own set of internal and external controls. This has led to model predictions where environmental change causes R to exceed P, with consequent dieback of vegetation. However, empirical evidence suggests that the R : P ratio is constrained to a narrow range of about 0·4-0·5. Physiological explanations for the narrow range are not conclusive. The aim of this work is to introduce a novel perspective by theoretical study of the quantitative relationship between the four carbon fluxes of P, R, growth and storage (or its inverse, remobilization). Methods Starting from the law of conservation of mass - in this case carbon - equations are derived for the relative magnitudes of all carbon fluxes, which depend on only two parameters: the R : P ratio and the relative rate of storage of carbon in remobilizable reserves. The equations are used to explain observed flux ratios and to analyse incomplete data sets of carbon fluxes. Key Results The storage rate is shown to be a freely varying parameter, whereas R : P is narrowly constrained. This explains the constancy of the ratio reported in the literature. With the information thus gained, a data set of R and P in grassland was analysed, and flux estimates could be derived for the periods after cuts in which plant growth is dominated by remobilization before photosynthesis takes over. Conclusions It is concluded that the relative magnitudes of photosynthesis, respiration, growth and substrate storage are indeed tightly constrained, but because of mass conservation rather than for physiological reasons. This facilitates analysis of incomplete data sets. Mechanistic models, as the embodiment of physiological mechanisms, need to show consistency with the constraints.
Forfattere
S Jacob Eivind Vangdal A Torricelli L Spinelli M Vanoli P Eccher Zerbini L M M Tisjkens E MadietaSammendrag
Absorption and scattering of laser light pulse passing through the fruit determine among others, the optical properties of the product. Efforts have been made in the recent past to utilize innovative techniques such as time-resolved reflectance spectroscopy (TRS) to study the quality aspects of different fruit such as nectarines. These optical properties have been well related to firmness, sugars, acids and other quality attributes. TRS measurements were performed on ‘Jubileum" plums at two different wavelengths: 670 nm and 758 nm. The fruit were harvested in Norway and brought to Italy under protected conditions. After sorting the fruit by size, TRS measurements were made and the fruit were randomized for different examinations of quality aspects. It was observed that the absorption coefficient (μa) increased for both wavelengths as ripening progressed towards the melting stage of the fruit. The μa values at 670 nm were higher than those at 758 nm. The higher rate in the μa was distinguishable from the third day onwards as the fruit ripened. Similarly, it was interesting to note that the internal colour measured after destructing the fruit related well with the TRS absorption coefficient (μa), i.e., a decrease in the CIE L* (towards darker region) and b* (towards blue) value along with an increase in a* (towards red) from third day of storage.
Sammendrag
VKM"s Panel 9 gives the following main conclusions of part 2 of the risk assessment: 1) Under the present climatic conditions, and if no control measures are taken, an introduction of PWN to the PRA area will not cause increased pine tree mortality. The level of uncertainty of this assessment is low. 2) Assuming the IS92a climate change scenario for the period 2000-2049 (RegClim), which involves a ~2 ºC temperature increase by the end of the period, an introduction of PWN to the PRA area will, if no control measures are taken, cause a minor increase in pine tree mortality (300 trees per year on average). The mortality can become larger if the temperature increases more than 2 ºC, and will gradually increase with time after 2049 due to spread of PWN. The level of uncertainty of these assessments is medium to high. 3) Any effects of PWN presence in the PRA area on export of wood and wood products will be of little importance. The level uncertainty of this assessment is low. 4) It will be almost impossible to eradicate PWN once it has been introduced to the PRA area. The level of uncertainty of this assessment is low. 5) The cost of a single eradication event as described in the preliminary contingency plan for the PRA area is approximately 700 mill. NOK. Due to expected spread, the total cost of eradication attempts following one introduction event will be approximately 2000 mill. NOK for the first 50 years. The level of uncertainty of these assessments is medium. 6) The negative effects of the control measures on the environment will be major. The level of uncertainty of this assessment is low.