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.
2008
Forfattere
Nina Hovden Sæther Øystein Havrevoll Odd VangenSammendrag
Possible differences in gross and net feed balance and feed efficiency between two cattle breeds were studied. The “old” Black Sided Trønderfe and Nordlandsfe (STN) breed has hardly been selected for production traits the last decades due to a small population (800) while and the modern Norwegian Red (NR) breed (230 000) has been bred according to a modern breeding programme with genetic improvements in milk, growth, health and fertility. The study was done on lactating cows in three indoor feeding periods; ten cows in each breed group, fed roughage ad-lib and an adjusted level of concentrates. Feed intake, milk yield and -quality were recorded every week, and live weight was recorded every month. The gross energy balance was defined as energy intake subtracted by energy in produced milk, while the gross energy efficiency was computed by dividing energy in produced milk by energy intake. At the net energy level it was adjusted for energy loss or release from body tissue gain or loss. The results show that in spite of the large difference in production level, there were no breed differences in energy balance, neither at the gross nor at the net level. However, the NR was significantly more efficient when comparing gross feed efficiency, but there were no breed differences in net feed efficiency.
Sammendrag
Det er ikke registrert sammendrag
Forfattere
Øystein Johnsen Igor A. Yakovlev Daniel Kwaku A. Asante Anne Eskild Nilsen Harald Kvaalen Carl Gunnar FossdalSammendrag
In forest trees, environmental conditions during the reproduction can greatly influence progeny performance. We here suggest that temperature during zygotic embryogenesis and seed maturation regulates an “epigenetic memory” in the progeny, involving differential expression of genes that may regulate bud phenology, cold acclimation and embryogenesis in Norway spruce. Conditions colder than normal advance the timing whilst temperatures above normal delay the onset of these processes. The altered performance lasts for many years. The seedlings actually remember the temperatures and photoperiod prevailing during zygotic embryogenesis and seed maturation. We show for the first time that regenerated plants, cloned through somatic embryogenesis, express a memory of the temperatures applied during embryo development whilst growing in a common greenhouse environment. The warmer the in vitro temperature applied, the later the regenerated plants formed terminal buds in the common environment the second growth season. The differences were very large, and similar in size to a provenance separation of 4 – 6 degrees of latitude. To study a molecular mechanisms of a memory from embryo development identical crosses were performed, seed were produced in different temperature regimes (cold and warm embryonic history) and seedling were grown under long day (LD = continuous light) and short day (SD = 12 h night) conditions. We have prepared two subtracted cDNA libraries, forward and revers, representing genes predominantly expressed in plants growing from seeds obtained after embryogenesis in cold environment (CE) and warm environment (WE) after short day treatment (going to bud set). Annotation reveals considerable differences in studied transcriptomes. More than 50% of contigs were unknown. So obtained subtracted libraries is a good source of candidate genes. We used quantitative RT–PCR to study the expression patterns of 34 chosen candidate genes. Just two putative genes among them with no matching in the Database and one reverse transcriptase show constitutively differential expression in progeny from CE and WE
Forfattere
Igor A. Yakovlev Daniel Kwaku A. Asante Carl Gunnar Fossdal Jouni Partanen Olavi Junttila Øystein JohnsenSammendrag
The initiation of growth and dormancy represents critical ecological and evolutionary trade-offs between survival and growth in most perennial plants and represents one of the most basic adaptations of trees to their environment. It is likely that they regulates differently: apical bud set and dormancy induction regulates by perception of short-day signal, but bud burst regulates mostly by temperature signals. We tried to dissect these processes on phenotypical and molecular levels. Seedlings for dormancy analysis were grown under long day (LD = continuous light) and short day (SD = 12 h night) conditions. We have prepared two SSH cDNA libraries, forward and reverse, representing genes predominantly expressed in plants after short day (SD) treatment (going to bud set) and continue growing at LD. Subtracted libraries had been partially sequenced for candidate genes seeking. Annotation reveals considerable differences in studied transcriptomes. More than 50% of contigs in LD library were represented by photosynthesis related genes and just nearly 6% in SD library. High differences were found in RNA synthesis and RNA processing, protein degradation, defense and transporting genes and also in transposable elements. Each library contains large number of unknown genes (mostly in SD). So obtained subtracted libraries is a good source of candidate genes, differently expressed during regulation of bud set. Bud burst initiation was studied on grafts from 15- and 30-year old Norway spruce within 3 time-points during autumn in natural (outdoor) and “forcing” (1 week, 12 h light and 20°C constant) conditions using earlier developed candidate genes (Yakovlev et al., 2007). We used quantitative RT–PCR to study the expression patterns of 58 chosen genes related for bud set and 34 genes – for bud burst. By the experiment conditions we could study only delayed genes and constitutively expressed early genes. Among the candidate genes found, the most interesting ones were the transcription factors, calcium censors, signaling, cold- and water stress related genes. The putative role of the studied genes in development regulation bud set and bud burst is discussed.
Forfattere
Helge SjursenSammendrag
Dikesvineblom tilhører den biologiske gruppen toårige ugras. Stengelen er rødfarget og snau. Rosettbladene er lysegrønne og snaue, oftest ikke delte. Stengelbladene er små og delte med stor endeflik. Har få store, gule korger. Opptrer som et plagsomt ugras på Sunnmøre, særlig i våt naturlig eller eldre eng og beite. Det er særlig storfe som er utsatt for forgiftning, dels akutt og dels kronisk. Bekjempelse: Bør hogges av før frøsetting. Kan også bekjempes ved å grave opp roten, eller kjemisk med preparater som inneholder mekoprop-p.
Forfattere
Vidar Selås Ronny Steen Sverre Kobro Terje Lislevand Ingvar StenbergSammendrag
In Norway, a positive relationship between spring numbers of lesser spotted woodpecker (Dendrocopos minor) and previous June temperatures has been interpreted as an effect of temperatures on woodpecker survival and reproduction during the breeding season. This article considers the possibility that woodpecker numbers are related to the abundance of the moth Argyresthia goedartella in the current year. Larvae and pupae of A. goedartella are important food for lesser spotted woodpeckers in early spring when few other surface-living invertebrates are available. The occurrence of this moth depends on the flowering of birch (Betula spp.) and alder (Alnus glutinosa), which in turn is influenced by June temperatures in the preceding year. Spring numbers of the lesser spotted woodpecker in two regions of Norway were compared with a trapping index of A. goedartella and weather variables assumed to influence the woodpeckers' breeding success and adult survival. The best multiple regression model included December temperatures and moth indices, supporting the hypothesis of a strong impact of A. goedartella on spring survival. Conservation strategies for the lesser spotted woodpecker should therefore focus not only on minimum areas of deciduous forests with decaying wood, but also on the availability of the moths' host trees, birch and alder.
Forfattere
Grete Lene SerikstadSammendrag
Frøugraset kan reguleres ved hjelp av mange direkte tiltak i økologisk drift. Summen av flere tiltak, både velprøvde i form av radrensing og hypping og bruk av biologisk kunnskap og nyutvikla redskaper kan til sammen holde ugraset nede.
Forfattere
Grete Lene SerikstadSammendrag
Frøugras kan regulereres ved hjelp av mange direkte tiltak i økologisk drift. Summen av flere tiltak, både velprøvde i form av radrensing og hypping og bruk av biologisk kunnskap og nyutvikla redskaper kan til sammen holde ugratet nede. Jordarbeiding i mørke, ugrasharving, flamming, børsting og lukevogn omtales.
Forfattere
Geir Kjølberg Knudsen Maria Bengtsson Sverre Kobro Gunnhild Jaastad Trond Hofsvang Peter WitzgallSammendrag
Apple fruit moth Argyresthia conjugella is a specialist seed predator of rowan Sorbus aucuparia. Large-scale synchronous fluctuation of seed production in rowan (i.e. named masting) drives the apple fruit moth to seek alternative host plants such as apple, during years when rowan berries are not available for oviposition. The role of plant volatile compounds in the attraction of gravid apple fruit moth females is studied in a laboratory wind tunnel. Volatiles from rowan branches with green berries stimulate female moths to fly upwind and to land at the odour source. By contrast, females are not attracted to rowan branches without green berries, and they are not attracted to apple, demonstrating that the chemical stimulus from rowan berries is required for attraction. Attraction to synthetic compounds identified from rowan, anethole and 2-phenyl ethanol confirms the role of plant volatiles in host finding. These two compounds, however, show a discrepant behavioural effect in wind tunnel and field tests. Field traps baited with 2-phenyl ethanol capture female moths but anethole does not produce significant captures. Wind tunnel tests produce the opposite results: moths fly upwind towards the anethole lure, whereas 2-phenyl ethanol is not attractive at all. Wind tunnel attraction to 2-phenyl ethanol is achieved by adding odour from a rowan branch without berries, which is not attractive on its own. This finding demonstrates that interaction with the background odour contributes to the behavioural effect of plant volatile stimuli in the field.
Forfattere
Tor Håkon SivertsenSammendrag
Some ideas connected to the scope of scientific work in agronomy and agro meteorology and the scope of the scientific principle are outlined. Then the concepts of ‘sustainability" and ‘sustainable agriculture" are presented, and the content of different definitions of these concepts is discussed. Especially the idea of sustainability as conservation of important relations is discussed.Then the concept and principle of an allodial farm or free farm, connected to Norwegian law and Norwegian traditions is presented and the history of the present law is briefly outlined. Also traditions for passage of farms from one generation to the next generation in a few other European countries are mentioned. Then the concept of allodial farm is connected to the challenges of global change of Northern Europe, and the existing ideas of commercial agriculture.The following idea is discussed: "The idea of changing the focus in agricultural production from maximizing the crop yield to keeping the ecological system of the farming and the local area sound and in shape". Man is an organism like other organisms. He ought to take care of his surroundings and the other species, to take care of a totality of biological systems on the Earth. Probably no god or gods will take care of him if he does not succeed in doing this. The content of the concepts of adaptation and mitigation connected to global change is also finally mentioned.