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.
2017
Sammendrag
The plant hormone auxin is a vital component for plant reproduction as it regulates the development of both male and female reproductive organs, including ovules and gynoecia. Furthermore, auxin plays important roles in the development and growth of seeds and fruits. Auxin responses can be detected in ovules shortly after fertilization, and it has been suggested that this accumulation is a prerequisite for the developmental reprogramming of the ovules to seeds, and of the gynoecium to a fruit. However, the roles of auxin at the final stages of ovule development, and the sources of auxin leading to the observed responses in ovules after fertilization have remained elusive. Here we have characterized the auxin readout in Arabidopsis ovules, at the pre-anthesis, anthesis and in the immediate post-fertilization stages, using the R2D2 auxin sensor. In addition we have mapped the expression of auxin biosynthesis and conjugation genes, as well as that of auxin transporting proteins, during the same developmental stages. These analyses reveal specific spatiotemporal patterns of the different auxin homeostasis regulators. Auxin biosynthesis genes and auxin transport proteins define a prepatterning of vascular cell identity in the pre-anthesis funiculus. Furthermore, our data suggests that auxin efflux from the ovule is restricted in an anther-dependent manner, presumably to synchronize reproductive organ development and thereby optimizing the chances of successful fertilization. Finally, de novo auxin biosynthesis together with reduced auxin conjugation and transport result in an enhanced auxin readout throughout the sporophytic tissues of the ovules soon after fertilization. Together, our results suggest a sophisticated set of regulatory cascades that allow successful fertilization and the subsequent transition of the female reproductive structures into seeds and fruits.
Forfattere
Mekjell MelandSammendrag
Hjå eple og plomme er det heilt turvande å regulera avlinga for å oppnå jamne avlingar av god kvalitet. I kommersiell dyrking er vanleg dyrkingspraksis å regulera avlinga kjemisk eller med hand under blomstringa eller på kartstadiet. Den kjemiske tynninga vert utført under blomstringa eller på liten kart. Då vert grovtynninga utført. I etterkant vert det justert for hand. Dei siste åra har det i Europa vorte arbeidd med alternative løysingar som er mekanisk tynning med maskin. Prinsippet er eit traktormontert utstyr med roterande trådar som vert køyrt på kvar sida av trerekkja under blomstringa. Ein del blomar vert då slått av slik at ei grovtynning vert gjort. Feltsesongen 2010 vart gjennomført to feltforsøk med utprøving av den tyske maskinen Baum for mekanisk blomstertynning, eit i eple med eplesorten Summerred poda på grunnstamma M9 og eit i plomme med plommesorten Opal poda på grunnstamma St. Julien A. Feltforsøka vart gjennomførde i kommersiell frukthagar nær Nibio Ullensvang........
Forfattere
Lars Sandved DalenSammendrag
Det er ikke registrert sammendrag
Sammendrag
Det er ikke registrert sammendrag
Forfattere
Juliana PerminowSammendrag
Det er ikke registrert sammendrag
Forfattere
Rolf Nestby Sebastien GuérySammendrag
OBJECT: Improved precision fertilization by introducing sensors and remote control to secure fruit yield and reduce nutrient leaching in soil culture. MATERIAL AND METHODS:We broadcasted before bedding and mulching 50 g m–2 of a multi-mineral fertilizer. Beds had two plant rows 20 cm apart, with plant distance of 25 cm. Experimental design was split plot with three replications and three treatments. Treatments: fertigation in large plots, cultivar in small plots and year. RESULTS: Plant development in the establishing year had no benefit of fertigation in addition to fertilizer given before bedding. When the yield is 3 kg m–2 a nutrient solution of 6 g N m–2 gave highest yield, using 4 g m–2 from two weeks before harvest and during harvest. ‘Florence’ and ‘Sonata’ developed well; however, ‘Florence’ had mildew on fruits in the last cropping year. ‘Korona’ presented well the first cropping year, but grew small fruits heavily infested by mildew in the last cropping year. CONCLUSION: Fertilization had effect on fruit yield. It is discussed how a fertilization schedule for the establishment year and cropping years can be adapted to plant development stages. Mildew infestation on fruits was dependent of cultivar and fertilization. Introducing sensors for recording of growth factors and in situ ion-levels of soil water nutrients, proved valuable.
Forfattere
Rolf Nestby Sebastien GuérySammendrag
Det er ikke registrert sammendrag
Sammendrag
Large-scale bark beetle outbreaks in northern conifer forests have already demonstrated huge impacts on forest economy, ecosystems and carbon dynamics. In North America, a historically unprecedented outbreak of the mountain pine beetle has expanded north- and eastwards beyond its historical range, and has reached epidemic levels in areas of northern British Columbia previously thought to be unsuitable for beetle survival. In Europe, the vast northern spruce forests have been spared from bark beetle outbreaks in the past, but here we review some recent observations and research results indicating that this may be undergoing change. For example, monitoring data of the most serious tree-killing bark beetle in Europe, Ips typographus, show a several-fold increase of the populations in its northern range during warm years. In the extensive spruce forests of northern Fennoscandia and Russia, a new phenomenon of tree-killing episodes by I. typographus has occurred in the last decade. Northern localities with one beetle generation per year in the past are now having more often two. Also other bark beetle species in the genus Ips have demonstrated a fast northward expansion in Europe, including one species contributing in bark beetle outbreaks of I. typographus in Central and Southern Europe.
Forfattere
Håvard Steinshamn Karl-Christian Mahnert Inga Marie Aasen Spiridoula Athanasiadou Heidi L Enemark Kristin SørheimSammendrag
Det er ikke registrert sammendrag
Forfattere
Håvard Steinshamn Karl-Christian Mahnert Inga Marie Aasen Spiridoula Athanasiadou Heidi L Enemark Kristin SørheimSammendrag
Det er ikke registrert sammendrag