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.
2009
Sammendrag
The most important and widespread disease on golf courses is Microdochium nivale. It is a psycrotrophic fungal plant pathogen that is the main cause of biotic winter injury in grasses in the temperate and sub-arctic climates, both with and without snow cover. It is an opportunistic pathogen, with the ability to attack plants under a wide range of environmental conditions. A large variation in both host preference and aggressiveness among isolates has been documented. It is speculated that these traits as well as competition between isolates may be dependent on temperature. The fungus is spread by infected seeds and from infected plants or debris. Besides seed transmitted inoculum, it is not clear whether the primary inoculum source is wind dispersed ascospores or soilborne/plant debris borne inoculum. Wind borne ascospores has been claimed to be the main inoculum source, but perithecia are hardly observed on grasses on Norway. The aim of the present project was obtain better understanding of what is the source of primary inoculum for snow mould caused by M. nivale; to understand how inoculum of M. nivale survives from spring to fall, and from year to year, to understand how climatic conditions affects the potential inoculum by monitoring symptoms on plants, occurrence of the fungus and growth characteristics in vitro of strains sampled from snow melt and through summer and autumn. To obtain such knowledge, surveys and sampling on selected golf courses was conducted. Snow mould symptoms and the occurrence of M. nivale in leaves and stems of grasses sampled from golf greens and foregreens was reduced during the growth season. We also found that M. nivale could be isolated from locations without visible symptoms. Despite a lower isolation rate in autumn, M. nivale was again isolated in some of the originally locations, the following spring. The M. nivale isolation rate was similar from sites located on greens compared to foregreens, and from greens located at more sunny sites compared to more shadowy located greens. We conclude that this fungus seem to survive from year to year within the same locations on greens and foregreens.
Forfattere
Belachew Asalf Tadesse Arne Stensvand David M. Gadoury Robert C Seem Andrew Dobson Anne-Marte TronsmoSammendrag
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Sammendrag
Regulation of flowering time in Arabidopsis thaliana is controlled by a network of pathways integrating environmental and internal signals. Two of these pathways, the vernalization and photoperiodic pathways, mediate responses to prolonged cold period and photoperiod, respectively. A number of A. thaliana populations from high-latitude and high-altitude locations in Norway were collected and phenotyped for flowering time in response to 5 photoperiods and 5 vernalization treatments. Vernalization and photoperiodic sensitivity were not correlated with latitude but rather with climatic factors such as winter temperature and precipitation that do not vary with latitude, especially in coastal environments. Coastal populations, both from subarctic and intermediate latitudes, were rather insensitive towards the length of the vernalization treatment but very sensitive towards differences in photoperiods. Stronger photoperiod sensitivity in coastal populations might be a necessary adaptation for sensing the onset of spring in regions with relatively mild and unpredictable winter climates as opposed to continental climates with more stable winters. FLC sequence variation was only partly associated with vernalization response, whereas variation in transcript levels of CRY2, TOC1 and GI was correlated with photoperiodic responses. This suggests that local adaptation of populations may be partly mediated by photoreceptors and circadian clock pathways.
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2008
Sammendrag
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Forfattere
Stig Morten Thorsen Lars Egil Haugen Mats HöglindSammendrag
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