Publications
NIBIOs employees contribute to several hundred scientific articles and research reports every year. You can browse or search in our collection which contains references and links to these publications as well as other research and dissemination activities. The collection is continously updated with new and historical material.
2014
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Nils VagstadAbstract
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Bruce Talbot Peter Tarp Morten NittebergAbstract
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Zhibo Hamborg Sissel Haugslien Jihong Liu Clarke Carl Jonas Jorge Spetz Dag-Ragnar Blystad Qing Wang YeonKyeong Lee Astrid H Sivertsen Gry SkjesethAbstract
Chrysanthemum stunt viroid (CSVd) was first reported in US in the 1940s and is widespread in the world wherever chrysanthemum is grown. Cryotherapy of shoot tips, a new biotechnology developed in the recent years, is a novel application of plant cryopreservation techniques that allows pathogen eradication at a high frequency. Existing studies have proven that this technique can efficiently eradicate pathogens such as virus, phytoplasma and bacterium. However, up to now, there has been no report on viroid eradication. In the present study, we attempted to establish a droplet vitrification cryotherapy method for Argyranthemum and to apply it to eradicate CSVd. Results obtained so far demonstrated that cryotherapy of shoot tips alone failed to eradicate CSVd from the infected shoot tips of Argyranthemum maderense ‘Yellow Empire’. Using in situ hybridization of CSVd and histological analysis, we found that CSVd can invade meristematic cells and at the same time, these cells were able to survive following cryotherapy. These findings explained why cryotherapy of shoot tips alone could not be efficient enough to eradicate CSVd from the diseased materials. Further studies combining cold treatment with cryotherapy are under investigation for CSVd eradication.
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Halvor B. Gjærum Kåre LyeAbstract
Puccinia rhodosensis sp. nov. is described on Tragopogon crocifolius from Rhodes, Greece. It differs from all other rust species on Tragopogon in having teliospores with completely smooth walls. SEM photos are provided for telia and teliospores.
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Margarita Novoa-Garrido Lise Aanensen Vibeke Lind Hans Jørgen Larsen Søren Krogh Jensen Espen Govasmark Håvard SteinshamnAbstract
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Abstract
Whole trees from energy thinnings constitute one of many forest fuel sources, yet ten widely applied supply chains could be defined for this feedstock alone. These ten represent only a subset of the real possibilities, as felling method was held constant and only a single market (combustion of whole tree chips) was considered. Stages included in-field, roadside landing, terminal, and conversion plant, and biomass states at each of these included loose whole trees, bundled whole trees or chipped material. Assumptions on prices, performances, and conversion rates were based on field trials and published literature in similar boreal forest conditions. The economic outcome was calculated on the basis of production, handling, treatment and storage costs and losses. Outcomes were tested for robustness on a range of object volumes (50–350 m3solid), extraction distances (50–550 m) and transport distances (10–70 km) using simulation across a set of discrete values. Transport was calculated for both a standard 19.5 m and an extended 24 m timber truck. Results showed that the most expensive chain (roadside bundling, roadside storage, terminal storage and delivery using a 19.5 m timber truck) at 158 € td−1 was 23% more costly than the cheapest chain (roadside chipping and direct transport to conversion plant with container truck), at 128 € td−1. Outcomes vary at specific object volumes and transport distances, highlighting the need to verify assumptions, although standard deviations around mean supply costs for each chain were small (6%–9%). Losses at all stages were modelled, with the largest losses (23 € td−1) occurring in the chains including bundles. The study makes all methods and assumptions explicit and can assist the procurement manager in understanding the mechanisms at work.
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It has been long known that thermal imaging may be used to detect stress (e.g. water and nutrient deficiency) in growing crops. Developments in microbolometer thermal cameras, such as the introduction of imaging arrays that may operate without costly active temperature stabilization, have vitalized the interest in thermal imaging for crop measurements. In this study, we have focused on the challenges occurring when temperature stabilization is omitted, including the effects of focal-plane-array (FPA) temperature, camera settings and the environment in which the measurements are performed. Further, we have designed and tested models for providing thermal response from an analog LWIR video signal (typical output from low-cost microbolometer thermal cameras). Finally, we have illustrated and discussed challenges which typically occur under practical use of thermal imaging of crops, by means of three cereal showcases, including proximal and remotely based (UAV) data acquisition. The results showed that changing FPA temperature greatly affected the measurements, and that wind and irradiance also appeared to affect the temperature dynamics considerably. Further, we found that adequate settings of camera gain and offset were crucial for obtaining a reliable result. The model which was considered best in terms of transforming video signals into thermal response data included information on camera FPA temperature, and was based on a priori calibrations using a black-body radiation source under controlled conditions. Very good calibration (r2>0.99, RMSE=0.32°C, n=96) was obtained for a target temperature range of 15-35°C, covering typical daytime crop temperatures in the growing season. However, the three showcases illustrated, that under practical conditions, more factors than FPA temperature may need to be corrected for. In conclusion, this study shows that thermal data acquisition by means of an analog, uncooled thermal camera may represent a possible, cost-efficient method for the detection of crop stress, but appropriate corrections of disturbing factors are required in order to obtain sufficient accuracy.