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.
2009
Authors
Anita Sønsteby Ola M. HeideAbstract
The effect of night temperature on short day (SD) floral induction in three June-bearing strawberry cultivars of different geographic origin was studied and compared with yield performance in the cool Nordic environment. At the optimum day temperature of 18°C, the SD flowering response of the cultivars ?Florence? and ?Korona? increased significantly with increasing night temperature from 9 to 18°C, while an optimum was reached at 15°C in ?Frida?, a cultivar selected under coolenvironment conditions in Norway. Also, while saturated flowering response was obtained with three weeks of SD treatment at all temperatures in ?Frida?, several plants of ?Florence? and ?Korona? failed to initiate flowers at 9°C night temperature even with five weeks of SD. The effect of extended SD period was particularly pronounced in ?Florence?. The slow SD floral induction response of ?Florence? was associated with a two-week delay of anthesis in subsequent long day (LD) conditions at 21°C. Performance studies of the same cultivars during two years under field conditions also demonstrated that the yield potential of ?Florence? was not realized under the climatic conditions prevailing at these locations. The yields varied significantly among the cultivars, ?Frida? having the highest yields, followed by ?Korona? and ?Florence? far below. It is concluded that, in the Nordic environment, autumn (September) night temperatures are obviously sub-optimal for yield performance of some June-bearing strawberry cultivars, and that this effect is mediated by autumn temperature effects on flower initiation responses. In the biennial-fruiting raspberry cultivar ?Glen Ample?, flowering and dormancy induction are controlled by the interaction of low temperature and short photoperiods. As neither process takes place at temperatures above 15°C regardless of the photoperiodic conditions, low temperature is of crucial regulatory importance. Environmental control of annual-fruiting cultivars is also briefly discussed.
Authors
Daniel P. Rasse Karin Knoth de Zarruk Line Tau StrandAbstract
No abstract has been registered
Authors
Heleen A. de Wit Rasmus Astrup Torill Engen-Skaugen Annika Hofgaard Glen Peters Line Tau StrandAbstract
No abstract has been registered
Abstract
No abstract has been registered
Abstract
Neozygites floridana is a fungus in the order Entomophthorales that infects and kills the two-spotted spider mite, Tetranychus urticae. The fungus is therefore of interest in the biological control of T. urticae. To obtain information that might help in the use of this fungus under practical conditions in strawberries and cucumbers we have tried to answer the following questions in a series of studies: 1) When, and at what infection levels does N. floridana occur in T. urticae populations in field grown strawberries in Norway? 2) How does N. floridana survive harsh climatic conditions (i.e winter) in Norway? 3) Where do N. floridana infected T. urticae move and sporulate on a plant? 4) How can N. floridana be inoculated in augmentative microbial control of T. urticae? Results show that the N. floridana infection level varies considerably throughout a season. T. urticae killed by N. floridana was found to sporulate surprisingly early in the season (first observation March 18) and infection early in the season is important for a good control of T. urticae. N. floridana was observed to over-winter as hyphal bodies in hibernating T. urticae females throughout the winter. Cadavers with resting spores were found from October to the end of January only. Cadavers then probably disintegrated, and resting spores were left on leaves, soil, etc. In a bioassay where a Norwegian N. floridana isolate was tested for numbers and distance of spores thrown at three different temperatures relevant to Norwegian conditions (13o, 18o, 23o C), results show that the highest numbers of spores (1886 and 1733 per cadaver) were thrown at 13o and 18o compared to 23o C (1302 per cadaver). Spores were thrown at the same distance (up to about 6 mm) at all three temperatures. These results show that the fungus may be a promising agent at temperatures relevant for strawberry production in countries located in Northern areas. Our attempt to inoculate N. floridana artificially in a strawberry field and also in greenhouse cucumbers has not been successful yet, but we are working to improve the methods in a new project titled "BERRYSYS -A system approach to biocontrol in organic and integrated strawberry production".
Authors
Mikael Ohlson Barbro Kristina Dahlberg Tonje Økland Kendrick J. Brown Rune HalvorsenAbstract
Forest fires release significant amounts of carbon dioxide into the atmosphere(1), but also convert a fraction of the burning vegetation to charred black carbon. Black carbon is hard to break down, and formation of this reserve therefore creates a long-term soil carbon sink(2-7). However, although soil black carbon pools are important for global carbon budgets, the spatial variation and dynamics of these pools are poorly understood(6-9). Here we examine the charcoal content of 845 soil samples collected from a broad range of boreal forest landscapes and climates in Scandinavia. We show that there is considerable variation in the distribution and carbon content of soil charcoal between forest landscapes; the landscape-level amount of soil carbon stored in charcoal ranged from 0 to 222 g Cm-2, with an average of 77 g Cm-2. The carbon concentration in the soil charcoal is significantly lower than that found in recently produced fresh charcoal, suggesting that charcoal carbon content decreases with time. Indeed, the median age of a subset of C-14-dated soil charcoal particles was 652 years, implying a rapid turnover compared with the expected median age of approximately 5,000 years if charcoal is persistent. Assuming that our measurements are representative of boreal forests worldwide, we estimate that boreal forest soils store 1 Pg of carbon in the form of charcoal, equivalent to 1% of the total plant carbon stock in boreal forests.
Authors
Richard Fischer Martin Lorenz Michael Köhl Georg Becher Oliver Granke Alexey Bobrinsky Tatyana Braslavskaya Wim de Vries Matthias Dobbertin Philipp Kraft Daniel Laubhann Natalia Lukina Hans Dieter Nagel Gert Jan Reinds Hubert Sterba Svein Solberg Silvia Stofer Walter SeidlingAbstract
No abstract has been registered
Authors
Dugassa N. Feyissa Trond Karsten Løvdal Kristine Marie Olsen Rune Slimestad Cathrine LilloAbstract
The bHLH transcription factors EGL3 (ENHANCER OF GLABRA3) and its close homologue GL3 (GLABRA3) are important regulators of the anthocyanin pathway in Arabidopsis thaliana, and together with TTG1 (a WD40 repeat protein) and MYB transcription factors regulate specific genes in the pathway. In response to nitrogen depletion, the MYB genes PAP1/PAP2 (production of anthocyanin pigment 1/2) and GL3 are strongly induced, and anthocyanin synthesis is activated in seedlings and rosette stage plants. In this study we show that anthocyanins accumulate in both wild type and egl3, but not in gl3 loss-of-function mutants when depleted of nitrogen. Several structural genes of flavonoid metabolism including CHS (chalcone synthase), FLS1 (flavonol synthase 1) and ANS (anthocyanidin synthase) were induced in response to nitrogen depletion in wild type as well as in the egl3 and gl3 mutants. Strikingly, in the gl3 mutant DFR (dihydroflavonol-4-reductase) transcript level was only 2% of the levels in wild type or egl3 mutant. Hence, low expression of DFR appears to be the bottleneck preventing anthocyanin synthesis in the gl3 mutant. The specific effect on DFR, but not ANS is compatible with involvement of the MYBL2 inhibitor.
Authors
Christian Guido Bruckner Matthias Labrenz Thomas Schott Jana Grote Klaus JürgensAbstract
No abstract has been registered
Abstract
Myrmica specioides Bondroit, 1918 and Formica cunicularia Latreille, 1798 are recorded in Norway for the first time. Both species were found in 2008 at Jeløya, Østfold County in South-Eastern Norway. A total of 54 outdoor-living ant species are now known to occur in Norway.