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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.

2019

Til dokument

Sammendrag

The viability and physiological state of brown macroalgae Fucus vesiculosus and its associated epiphytic bacteria exposed to diesel water-accommodated fraction (WAF), as well as the capacity of this association to deplete petroleum hydrocarbons (HCs) were experimentally tested. After a 6-day exposure treatment, the algal-surface associated bacteria were identified as primarily hydrocarbon-oxidising bacteria (HOB), and the algal-HOB association was able to deplete petroleum hydrocarbons from the diesel WAF by 80%. The HOB density on the algal surface exposed to diesel WAF was 350% higher compared to the control (i.e. HOB density on the algal surface exposed to ambient seawater), which suggest that they actively proliferated in the presence of hydrocarbons and most likely consumed hydrocarbons as their primary organic substrate. Exposure to diesel WAF did not affect the metabolic activity of F. vesiculosus. Higher lipid peroxidation was observed in F. vesiculosus exposed to diesel WAF while catalase concentration decreased only during the first day of exposure. Results suggest F. vesiculosus is tolerant to oil pollution and the algal-HOB association can efficiently deplete petroleum hydrocarbons in oil-contaminated seas.

Sammendrag

Green-sprouting potato seed tubers in light and elevated temperatures are vital for production in short-season climates. Using light-emitting diodes (LEDs) to inhibit sprout elongation during pre-sprouting may represent an energy-efficient alternative to traditional indoor light sources. Sprout growth inhibition and some photomorphogenic responses were therefore examined in potato cultivars exposed to LEDs of different wavelength maxima and irradiance rates. Red LED (660 nm) produced the strongest inhibition of sprout elongation at very low irradiances 10–100 nmol m−2 s−1, while far-red LED (735 nm) produced the strongest inhibition at higher irradiances. This inhibitory pattern was similar in all cultivars, although the degree of inhibition varied. The colour of sprouts and tuber skin remained etiolated under far-red LED, in contrast to LEDs between 380 and 660 nm which developed green colour intensity in an irradiance-dependent manner. Mixtures of red and far-red light, and pulses including red/far-red reversals did not produce stronger inhibition, except in some instances where total fluence was increased. Furthermore, green-sprouting under different LED colours did not seem to affect subsequent emergence and growth after planting. The current results suggest an involvement of multiple phytochromes in de-etiolation and sprout growth inhibition in seed potato tubers, which may be selectively utilised in LED-based green-sprouting in red and far-red wavelengths.

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Sammendrag

Nitrous oxide (N2O) emissions from cultivated soils correlate positively with the amount of N-fertilizer applied, but a large proportion of the annual N2O emission occurs outside the cropping season, potentially blurring this correlation. We measured the effect of split-N application (total N addition varying from 0 to 220 kg N ha−1) on N2O emissions in a spring wheat plot trial in SE Norway from the time of split-N application until harvest, and during the following winter and spring thaw period. N2O emissions were largest in the two highest N-levels, whereas yield-scaled emission (N2O intensity) was highest in the 0 N treatment. Nitrogen yield increased by 23% when adding 80 kg N ha−1 compared to adding 40 kg N ha−1 as split application, while corresponding N2O emissions were reduced by 16%. No differences in measured emissions between the N-fertilization levels were observed during the winter period or during spring thaw. Measurements of soil air composition below the snow pack revealed that N2O production continued throughout winter as the concentration in the soil air increased from 0.37 to 30.0 µL L−1 N2O over the 3 months period with continuous snow cover. However, only 7–28% of the N2O emitted during spring thaw could be ascribed to accumulated N2O, indicating de novo production of N2O in the thawing soil. The direct effect of split-N fertilizer rate on N2O emissions in sub-boreal cereal cropping was limited to the first 15–21 days after N-addition.

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Sammendrag

Flowering performance and phenology of six new pear cultivars of Nordic origin were examined during a 12 year period. The seasonal timing of shoot growth and flower initiation were monitored in three years. The morphological floral stages of the flower bud formation process were examined for the cultivar ‘Celina’. Seven floral stages were identified and described. The date of full bloom varied between years as a function of the currently accumulated heat sum in early spring. Still, the earliness ranking of the cultivars was consistent across years for both flower initiation and blooming. The cultivars ‘Anna’ and ‘Ingeborg’ consistently initiated floral primordia 2–3 weeks earlier than ‘Celina’, ‘Clara Frijs’, ‘Fritjof’ and ‘Kristina’, and this was accompanied with 4–5 days earlier blooming in the following spring. The early flower initiation cultivars ‘Anna’ and ‘Ingeborg’ also had richer flowering than the late-blooming cultivars. ‘Fritjof’ was identified as a suitable pollinator for ‘Celina’ in the Nordic climate. Comparison of the flowering phenology of pear and apple cultivars showed that while the pears, on average, flowered a week ahead of the apples, they initiated flower primordia almost two weeks later, thus rendering the intervening period approximately three weeks longer in pear than in apple