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.
2017
Abstract
No abstract has been registered
Abstract
Phosphorus (P) is one of the main limiting factors for crop productivity while rhizosphere organic anions have been hypothesized to play an important role in P acquisition. Sampling in a long-term field experiment was carried out in order to understand the impact of long-term differences in P fertilization on secretion of organic anions under field conditions. Rhizosphere organic anions were extracted and analyzed every week from three leaves stage to completed flowering stage of wheat (Triticum aestivum) grown on plots that have received 0 (P0) or 48 (P48) kg P ha−1 year−1 since 1966. The study showed that it is possible to extract and quantify rhizosphere organic anions from field plots. In P48 plots, root P concentrations decreased around 40 % at the early stages (before heading), compared with the first sampling, and then increased slightly, while plants grown in P0 plots showed the opposite trend. Malate was the main organic anion secreted throughout all the wheat growth stages. Rhizosphere citrate and malate showed negative and positive correlations (P < 0.05) respectively with root P concentrations at 29 and 42 days after emergence (DAE). Rhizosphere organic anion concentrations were quite low until 29 DAE and then increased up to 4–10-fold until 42 DAE; these concentrations declined at later stages, indicating that root-released organic anions may have been affected by developmental stage and root P concentration. The present study provides valuable information about the relationship between rhizosphere organic anions and various P concentrations of wheat grown in the field.
Authors
Ioannis Dimitriou Blas Mola-YudegoAbstract
Trees of genus Populus (in our context primarily poplars) are predominantly grown in Sweden in small plantations on arable land in southern and central parts of the country to produce biomass for energy and other purposes. This study evaluated the effects (i) of poplar plantations on groundwater quality, by determining differences in leaching of nitrogen and phosphorus to groundwater, and (ii) of poplar and hybrid aspen plantations on soil quality in terms of carbon in the top- and subsoil. The study was conducted comparing Populus plantations in Sweden with adjacent fields with cereals and grasslands. The experiment concerning the groundwater leaching was conducted in eight poplar plantations along three growing seasons (2012–2015). For the soil carbon experiments, 19 poplar and two hybrid aspen plantations and the respective reference fields were sampled. NO3-N leaching from poplar plantations was significantly lower than that from reference fields with cereals, but not when compared with grasslands. Spring NO3-N leaching was significantly lower in poplars than in the reference fields, whereas leaching of NO3-N in autumn did not differ. Concentrations of PO4-P in the groundwater of poplar plantations were lower compared to the respective ones of the reference fields. There were no clear trends observed when comparing carbon concentrations in the topsoil of the poplar and hybrid aspen plantations compared to the respective adjacent reference fields. For the subsoil, the average carbon concentrations in the poplar and hybrid aspen plantations were equal to the respective ones of cereals, but were higher when compared to grassland.
Abstract
Partial migration is common in a large variety of taxa in seasonally variable environments. Understanding the mechanisms underlying migration is important, as migration affects individual fi tness. Migratory herbivores bene fi t from delayed forage maturation and hence higher food quality during migra- tion and at their summer range, termed the forage maturation hypothesis (FMH). The link between diet quality and rumination time allows migrants eating a higher quality diet to spend less time on rumination, and they can thus allocate more time to additional feeding. However, such an argument implicitly assumes that deer are energy maximizers, while studies have reported also time minimization strategies under risk of predation. Male and female distributions are limited by different factors linked to both body size differ- ences and reproductive strategies, but there is no study investigating differences in activity pattern accord- ing to the individual migratory patterns for male and female deer. We here unify the FMH with the hypotheses predicting sex-speci fi c time allocation strategies. To test predictions of sex-speci fi c activity of resident and migratory red deer ( Cervus elaphus ), we analyzed activity data of 286 individuals that were fi tted with GPS collars from a population in western Norway. While migrants were more active during the migration itself, we found no differences in activity pattern between migrant and resident deer during the main growth season, neither in terms of proportion of daily time active nor in terms of daily mean movement speed, thus rejecting that deer were energy maximizers. Overall, we found that females were more active during the main growth season even after controlling for body size differences. These patterns are consistent with patterns predicted from sexual segregation theory linked to the reproductive strategy hypothesis. Our study highlights how the understanding of migration can be advanced by considering it in the context of different reproductive strategies of males and females.
Authors
Merete Wiken Dees Simeon Rossmann Monica Skogen Vinh Hong Le Arnaud Lefrancois Abdelhameed Elameen Borghild Glorvigen Alison K. Lees Jan van der Wolf May Bente BrurbergAbstract
No abstract has been registered
Abstract
Epigenetic memory in Norway spruce affects the timing of bud burst and bud set, vitally important adaptive traits for this long-lived forest species. Epigenetic memory is established in response to the temperature conditions during embryogenesis. Somatic embryogenesis at different epitype inducing (EpI) temperatures closely mimics the natural processes of epigenetic memory formation in seeds, giving rise to epigenetically different clonal plants in a reproducible and predictable manner, with respect to altered bud phenology. MicroRNAs (miRNAs) and other small non-coding RNAs (sRNAs) play an essential role in the regulation of plant gene expression and may affect this epigenetic mechanism. We used NGS sequencing and computational in silico methods to identify and profile conserved and novel miRNAs among small RNAs in embryogenic tissues of Norway spruce at three EpI temperatures (18, 23 and 28◦C). We detected three predominant classes of sRNAs related to a length of 24 nt, followed by a 21–22 nt class and a third 31 nt class of sRNAs. More than 2100 different miRNAs within the prevailing length 21–22 nt were identified. Profiling these putative miRNAs allowed identification of 1053 highly expressed miRNAs, including 523 conserved and 530 novels. 654 of these miRNAs were found to be differentially expressed (DEM) depending on EpI temperature. For most DEMs, we defined their putative mRNA targets. The targets represented mostly by transcripts of multiple-repeats proteins, like TIR, NBS-LRR, PPR and TPR repeat, Clathrin/VPS proteins, Myb-like, AP2, etc. Notably, 124 DE miRNAs targeted 203 differentially expressed epigenetic regulators. Developing Norway spruce embryos possess a more complex sRNA structure than that reported for somatic tissues. A variety of the predicted miRNAs showed distinct EpI temperature dependent expression patterns. These putative EpI miRNAs target spruce genes with a wide range of functions, including genes known to be involved in epigenetic regulation, which in turn could provide a feedback process leading to the formation of epigenetic marks. We suggest that TIR, NBS and LRR domain containing proteins could fulfill more general functions for signal transduction from external environmental stimuli and conversion them into molecular response. Fine-tuning of the miRNA production likely participates in both developmental regulation and epigenetic memory formation in Norway spruce.
Authors
Steffen Werne Felix Heckendorn Michael Roleda L Baumgartner Eduarda Molina-Alcaide A Drewek Vibeke LindAbstract
No abstract has been registered
Authors
Andre van Eerde Johanna Gottschamel Hege Særvold Steen Sissel Haugslien Anna-Marja Aura Stephanie Ruf Ralph Bock Jihong Liu ClarkeAbstract
No abstract has been registered
Authors
Eduarda Molina-Alcaide Maria Dolores Carro Michael Roleda Martin Riis Weisbjerg Vibeke Lind Margarita Novoa-GarridoAbstract
Seaweeds have potentials as alternative feed for ruminants, but there is a limited knowledge on their nutritive value. Seven seaweed species collected along the coast above the Arctic circle of Norway, both in spring and autumn, were assessed for nutrients and total polyphenols (TEP) content, gas production kinetics and in vitro rumen fermentation in batch cultures of ruminal microorganisms. The seaweeds were three red species (Mastocarpus stellatus, Palmaria palmata and Porphyra sp.), three brown species (Alaria esculenta, Laminaria digitata and Pelvetia canaliculata) and one green species (Acrosiphonia sp.). Additionally, the abundance and diversity of total bacteria, protozoa and archaea in the cultures with the three red seaweeds collected in spring were analyzed by quantitative PCR and PCR-DGGE, respectively. The crude protein (CP) content varied widely. Pelvetia had the greatest (P < 0.001) ether extract (EE) content. Non-structural carbohydrates (NSC) content varied from 135 to 541 g/kg DM with brown seaweeds having the greatest values. Ash and CP contents were higher in spring than in autumn (P = 0.020 and 0.003, respectively), whereas concentrations of EE and NSC were not affected by collecting season (P = 0.208–0.341). The TEP values ranged from 1.46 to 50.3 mg/g dry matter (DM), and differed (P < 0.001) among seaweed species and collecting season, being greater in autumn than in spring. The DM effective degradability (DMED), estimated from gas production parameters for a rumen passage rate of 3.0% per h, ranged from 424 to 652 g/kg, the highest values were recorded for Mastocarpus stellatus and Porphyra sp. The lowest DMED values were registered for Pelvetia canaliculata and Acrosiphonia sp. In 24-h incubations (500 mg DM), Palmaria palmata had the highest (P < 0.05) volatile fatty acids (VFA) and methane production (4.34 and 0.761 mmol, respectively) and the lowest (P < 0.05) final pH values and acetate to propionate ratios (6.57 and 2.34, respectively). There were no differences (P > 0.05) among the other seaweeds in VFA production, but Porphyra sp. had the second highest methane production (P < 0.05; 0.491 mmol) compared with the other seaweeds (0.361 mmol; averaged value). The methane/total VFA ratio was not affected (P > 0.05) by either seaweed species or the collection season. Higher final pH (P < 0.05) and lower (P < 0.05) methane and VFA production, ammonia-N concentrations and DMED values were promoted by the fermentation of seaweed collected in autumn compared with those from spring. Among the red seaweeds, there were no species-specific differences (P > 0.05) in the abundance or the diversity of total bacteria, protozoa and archaea. In the PCR-DGGE analysis, samples were separated by the incubation run for all microbial populations analyzed, but not by seaweed species. The results indicate that seaweed species differ markedly in their in vitro rumen degradation, and that samples collected in autumn had lower rumen degradability than those collected in spring.
Authors
Melissa Magerøy Denis Lachance Sharon Jancsik Genevieve Parent Armand Seguin John Mackay Joerg BohlmannAbstract
No abstract has been registered