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.
2010
Sammendrag
Norway spruce expresses a temperature-dependent epigenetic memory from the time of embryo development, which thereafter influences the timing bud phenology. MicroRNAs (miRNAs)are endogenous small RNAs, exerting epigenetic gene regulatory impacts. We have tested for their presence and differential expression. We prepared concatemerized small RNA libraries from seedlings of two full-sib families, originated from seeds developed in a cold and warm environment. One family expressed distinct epigenetic effects while the other not. We used available plant miRNA query sequences to search for conserved miRNAs and from the sequencing we found novel ones; the miRNAs were monitored using relative real time-PCR. Sequencing identified 24 novel and four conserved miRNAs. Further screening of the conserved miRNAs confirmed the presence of 16 additional miRNAs. Most of the miRNAs were targeted to unknown genes. The expression of seven conserved and nine novel miRNAs showed significant differences in transcript levels in the full-sib family showing distinct epigenetic difference in bud set, but not in the nonresponding full-sib family. Putative miRNA targets were studied. Norway spruce contains a set of conserved miRNAs as well as a large proportion of novel nonconserved miRNAs. The differentially expression of specific miRNAs indicate their putative participation in the epigenetic regulation.
Sammendrag
Det er ikke registrert sammendrag
Forfattere
Aruppillai Suthaparan Sissel Torre Arne Stensvand Maria Herrero Rolf Inge Pettersen David M. Gadoury Hans Ragnar GislerødSammendrag
When rose plants bearing colonies of Podosphaera pannosa were placed in a wind tunnel, the number of conidia trapped was directly proportional to intensity of daylight-balanced (white) light from 5 to 150 mu mol m(-2) s(-1). Illumination of samples using blue (420 to 520 nm) light-emitting diodes (LEDs) increased the number of conidia trapped by a factor of approximately 2.7 over white light but germination of conidia under blue light was reduced by approximately 16.5% compared with conidia germination under white light. The number of conidia trapped under far-red (>685 nm) LEDs was approximately 4.7 times higher than in white light, and 13.3 times higher than under red (575 to 675 nm) LEDs, and germination was not induced compared with white light. When mildewed plants were exposed to cycles of 18 h of white light followed by 6 h of blue, red, far-red light, or darkness, light from the red LEDs reduced the number of conidia trapped by approximately 88% compared with darkness or far-red light. Interrupting the above dark period with 1 h of light from red LEDs also reduced the number of conidia trapped, while a 1-h period of light from far-red following the 1 h of light from red LEDs nullified the suppressive effect of red light. Our results indicate that brief exposure to red light during the dark interval may be as effective as continuous illumination in suppressing powdery mildew in greenhouse rose plant (Rosa x hybrida).
Forfattere
David M. Gadoury Belachew Asalf Tadesse M Heidenreich Maria Herrero MJ Welser Robert C Seem Anne Marte Tronsmo Arne StensvandSammendrag
A collection of four clonal isolates of Podosphaera aphanis was heterothallic and was composed of two mutually exclusive mating types. Cleistothecial initials approximate to 20 to 30 mu m in diameter were observed within 7 to 14 days after pairing of compatible isolates and developed into morphologically mature ascocarps within 4 weeks after initiation on both potted plants maintained in isolation and in field plantings in New York State and southern Norway. Ascospores progressed through a lengthy maturation process over winter, during which (i) the conspicuous epiplasm of the ascus was absorbed; (ii) the osmotic potential of the ascospore cytoplasm increased, resulting in bursting of prematurely freed spores in water; and, finally, (iii) resulting in the development of physiologically mature, germinable, and infectious ascospores. Release of overwintered ascospores from field collections was coincident with renewed plant growth in spring. Overwintered cleistothecia readily dehisced when wetted and released ascospores onto glass slides, detached strawberry leaves, and leaves of potted plants. Plant material exposed to discharged ascospores developed macroscopically visible mildew colonies within 7 to 10 days while noninoculated controls remained mildew free. Scanning electron and light microscopy revealed that cleistothecia of P. aphanis were enmeshed within a dense mat of hyphae on the persistent leaves of field-grown strawberry plants and were highly resistant to removal by rain while these leaves remained alive. In contrast, morphologically mature cleistothecia on leaves of nine deciduous perennial plant species were readily detached by simulated rain and seemed adapted for passive dispersal by rain to other substrates. Contrary to many previous reports, cleistothecia appear to be a functional source of primary inoculum for strawberry powdery mildew. Furthermore, they differ substantially from cleistothecia of powdery mildews of many deciduous perennial plants in their propensity to remain attached to the persistent leaves of their host during the intercrop period.
Sammendrag
Roseroot, Rhodiola rosea, is a perennial herbaceous plant of the family Crassulaceae. The rhizomes of 95 roseroot clones in the Norwegian germplasm collection were analysed and quantified for their content of the bioactive compounds rosavin, salidroside, rosin, cinnamyl alcohol and tyrosol using HPLC analysis. All five bioactive compounds were detected in all 95 roseroot clones but in highly variable quantities. The ranges observed for the different compounds were for rosavin 2.90-85.95mgg-1, salidroside 0.03-12.85mgg-1, rosin 0.08-4.75mgg-1, tyrosol 0.04-2.15mgg-1 and cinnamyl alcohol 0.02-1.18mgg-1. The frequency distribution of the chemical content of each clone did not reflect a certain geographic region of origin or the gender of the plant. Significant correlations were found for the contents of several of these bioactive compounds in individual roseroot clones. A low, but not significant correlation was found between AFLP markers previously used to study the genetic diversity of the roseroot clones and their production of the chemical compounds. The maximum level of rosavin, rosin and salidroside observed were higher than for any roseroot plant previously reported in literature, and the roseroot clones characterized in this study might therefore prove to be of high pharmacological value.
Sammendrag
This review describes the effects of the current and emerging lighting technologies on plants, and the plant-mediated effects on herbivorous and beneficial arthropods in high-technology year-round greenhouse production, where light quality, quantity and photoperiod differ from the natural environment. The spectrum provided by the current lighting technology, high-pressure sodium lamp (HPSL), differs considerably from that of solar radiation. The major plantmediated effects on arthropods were predicted to result from (a) extended photoperiods and lower light integrals, (b) the attenuation of ultraviolet (UV) wavelengths, particularly UV-B, (c) the high red: far-red (R : FR) ratio and lower blue : red (B : R) in comparison with solar radiation and (d) the high proportion of yellowwavelengths during winter months. Of these light factors (a-d) (ceteris paribus), (a) and (b) were hypothesised to result in increased performance of herbivores in winter months, whereas the high R : FR ratio decreased herbivore performance or not affected it, at least when interlights are used. The predictions obtained on the basis of this review are also discussed in relation to the modifying factors prevailing in these production environments: enriched CO2 levels, high nutrient amounts, optimised irrigation and temperatures optimal for plants" needs. Based on the carbon/nitrogen and growth/differentiation balance theories, these modifying factors tend to produce plants that allocate most resources to growth at the expense of defensive secondary metabolism and physicochemical defensive structures. At the end, this review discusses knowledge gaps and future research prospects, in which light-emitting diodes, the emerging lighting technology, play an important role by enabling the targeted manipulation of plant responses to different wavelengths.
Forfattere
Brita Toppe Arne Hückstädt María L. Herrero Jafar Razzaghian Andrew Dobson Hans Ragnar GislerødSammendrag
Moderat auka av frie koparion i næringsløysinga er kjent å kunna redusera spreiing av pseudosoppar som Pythium og Phytophthora. Effekten på Fusarium er meir usikker. Laboratorieforsøk gjennomført i prosjektet "Redusert åtak av rotsjukdomar i norske prydplanter" viser at konsentrasjon av frie koparion må aukast til relativt høge nivå for å hindra sporespiring hos Fusarium foetens.
Forfattere
Isabella Børja Nicholas Clarke J Dreslerová Toril Drabløs Eldhuset Roman Gebauer V Gryc Paal Krokene Nina Elisabeth Nagy J Urban Daniel VolaříkSammendrag
Det er ikke registrert sammendrag
Forfattere
Filipa Cox Nadia Barsoum Martin I. Bidartondo Isabella Børja Erik Lilleskov Lars Ola Nilsson Pasi Rautio Kath Tubby Lars VesterdalSammendrag
Det er ikke registrert sammendrag
Sammendrag
Det er ikke registrert sammendrag