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.
2024
Authors
Mirjana SadojevicAbstract
Environmental control of growth and flowering is generally well understood in raspberries, but a complete understanding of the processes is missing in blackberries. To get a better understanding of growth and flowering in blackberries, five cultivars, ‘Loch Ness’, ‘Loch Tay’, ‘Natchez’, ‘Ouachita’, and ‘Sweet Royalla’, were studied in the phytotron at 16°C and 12, 13, 14 and 15h photoperiod, and under natural temperature and daylength conditions at Apelsvoll, Norway (60.7° N). The results demonstrate that origin and genetic background of cultivars play a crucial role in how they respond to environmental signals. ‘Natchez’ had a critical photoperiod of 14h for cessation of growth at 16°C, while ‘Loch Ness’ continued to grow independently of photoperiod treatment. Photoperiod in the 12-15h range was not critical for flower bud initiation in ‘Natchez’ and ‘Loch Ness’. All five cultivars initiated flower buds before cessation of growth under out-door conditions. In both experiments, the cultivars that reached growth cessation first, also had the most advanced flower buds, except for ‘Ouachita’. Flower bud initiation in ‘Loch Ness’ and ‘Natchez’ began in the mid-section of the cane and continued in both basipetal and acropetal directions. Three ‘Loch Ness’ plants from each photoperiod treatment were forced in the greenhouse after sufficient chilling to examine the flowering performance of the buds that were initiated before growth cessation. Plants at 15h photoperiod, had the highest percentage of flowering nodes, most flowers per plant and fewest days to anthesis at forcing, but all plants from all treatments developed flowers. The position of the flowering nodes along the cane corresponded to the position of the initiated flower buds dissected in ‘Loch Ness’ prior to chilling. The results suggest that temperature, rather than photoperiod, may be the main factor affecting both growth cessation and flower bud initiation in blackberries.
Authors
Mirjana SadojevicAbstract
No abstract has been registered
Abstract
The brown marine macroalga Alaria esculenta contains phlorotannins as polyphenolic compounds in its cell walls. This study aimed to understand their antioxidant effects on preserving the lipids in fillets of freshly-slaughtered farmed Atlantic salmon (Salmo salar). First, soluble phlorotannins were extracted from wild-grown population of A. esculenta in North Norway (Bodø) using solid/liquid extraction. A small-scale solid/liquid extraction (15 mg mL−1) with 70% acetone showed that 84% of total soluble phlorotannins (25.10 mg g−1 dry weight) were extracted after the first out of four extraction steps. In a large-scale extraction (3 mg 400 mL−1), the contents of soluble phlorotannins and the DPPH-based antioxidant capacities (measured as IC50) in 70% acetone- and water-based crude extracts were similar. Water is preferred extraction solvent for the following experiment because it complies with food safety standards, may minimise work procedures and is in accordance with the principles of Green Chemistry. Secondly, the antioxidant properties of the soluble phlorotannins were tested through incubating salmon fillets (Norwegian Quality Cuts) in water-based extracts. After six days of storage on ice, the peroxide value of Alaria-treated fillets was lower compared to the control (without Alaria-extract), while the p-anisidine and free fatty acid values remained unchanged. This indicates the phlorotannins’ inhibitory effect on the formation of primary rather than secondary lipid oxidation products. This study demonstrated that the antioxidant properties of the soluble phlorotannins extracted from A. esculenta using water can preserve the nutritional value of salmon fillets to extend the seafood’s shelf-life.
Authors
Ralf RautenbergerAbstract
During the cultivation of Ulva fenestrata in a land-based aquaculture system, the colonisation of the water tanks’ surfaces and eventually the macroalgal biomass by the biofouling diatom Fragilariopsis oceanica compromises the production process. Since germanium dioxide (GeO2) is an effective growth inhibitor of diatoms, this study aimed to understand how it affects the presence of F. oceanica and the photosynthesis and growth of U. fenestrata as a primary parameter contribution to the biomass production. A toxicological dose-response experiment showed that the diatom’s growth was inhibited at the low GeO2 concentration of 0.014 mg l−1. In contrast, the photosynthetic performances and growth rates of U. fenestrata remained unaffected under a wide GeO2 concentration range (0.022–2.235 mg l−1) in small- and large-scale experiments in 1-l glass beakers and 100-l Plexiglass water tanks, respectively. In the latter, the diatom density in the tanks was reduced by 40 %. The costs arising from the use of GeO2 can range between €2.35 and €8.35 kg−1 fresh weight of produced U. fenestrata biomass under growth conditions resulting in growth rates of 20 and 11.5 % d−1, respectively. GeO2 is an effective agent to control biofouling diatoms such as F. oceanica during the land-based biomass production of U. fenestrata.
Abstract
Eutrophication of coastal ecosystems often stimulates massive and uncontrolled growth of green macroalgae, causing serious ecological problems. These green tides are frequently exposed to light intensities that can reduce their growth via the production of reactive oxygen species (ROS). To understand the physiological and biochemical mechanisms leading to the formation and maintenance of green tides, the interaction between inorganic nitrogen (Ni) and light was studied. In a bi-factorial physiological experiment simulating eutrophication under different light levels, the bloom-forming green macroalga Ulva rigida was exposed to a combination of ecologically relevant nitrate concentrations (3.8–44.7 µM) and light intensities (50–1100 µmol photons m−2 s−1) over three days. Although artificial eutrophication (≥ 21.7 µM) stimulated nitrate reductase activity, which regulated both nitrate uptake and vacuolar storage by a feedback mechanism, nitrogen assimilation remained constant. Growth was solely controlled by the light intensity because U. rigida was Ni-replete under oligotrophic conditions (3.8 µM), which requires an effective photoprotective mechanism. Fast declining Fv/Fm and non-photochemical quenching (NPQ) under excess light indicate that the combined photoinhibitory and PSII-reaction centre quenching avoided ROS production effectively. Thus, these mechanisms seem to be key to maintaining high photosynthetic activities and growth rates without producing ROS. Nevertheless, these photoprotective mechanisms allowed U. rigida to thrive under the contrasting experimental conditions with high daily growth rates (12–20%). This study helps understand the physiological mechanisms facilitating the formation and persistence of ecologically problematic green tides in coastal areas.
Authors
Ralf RautenbergerAbstract
No abstract has been registered
Authors
Rosaria Arena Giuseppe Renda Giovanna Ottaviani Aalmo Frédéric Debeaufort Concetta Maria Messina Andrea SantulliAbstract
The blue crab (Callinectes sapidus), originally from the western Atlantic Ocean, has recently spread to the Mediterranean and is now considered one of the one hundred most invasive species in that region. This opportunistic species, known for its adaptability to different temperatures and salinities, negatively impacts biodiversity and human activities such as fishing and tourism in the Mediterranean. However, the blue crab is gaining interest as a potential food resource due to its high nutritional value and delicate, sweet flavor. Its meat is rich in protein (14% to 30%), omega-3 fatty acids (EPA and DHA) and other essential nutrients beneficial for human health such as vitamins, and minerals. Utilizing this species in the production of new foods could help mitigate the negative impact of its invasiveness and offer economic opportunities. One challenge with this potential resource is the generation of waste. Approximately 6–8 million tonnes of crab shells are produced worldwide each year, leading to disposal problems and concerns regarding environmental sustainability. To improve economic and environmental sustainability, there is a need to valorize these residues, which are an important source of proteins, lipids, chitin, minerals, and pigments that can be processed into high-value-added products. However, especially in areas with industrial pollution, attention should be paid to the heavy metal (Cd and As) contents of blue crab shells. Studies suggest that blue crab by-products can be used in various sectors, reducing environmental impacts, promoting a circular economy, and creating new industrial opportunities.
Authors
Jakob GeipelAbstract
No abstract has been registered
Abstract
No abstract has been registered
Authors
Malin Olsen Wedaa Stine Samsonstuen Helge Bonesmo Bente Aspeholen Åby Erland Kjesbu Magne Bergfjord Rune OkstadAbstract
No abstract has been registered