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.
2012
Forfattere
Ivano Brunner Mark R. Bakker Robert G. Björk Yasuhiro Hirano Martin Lukac Xavier Aranda Isabella Børja Toril Eldhuset Heljä-Sisko Helmisaari Christophe Jourdan Bohdan Konôpka Bernat Claramunt López Carolina Miguel Pérez Hans Persson Ivika OstonenSammendrag
Background and Aims: Forest trees directly contribute to carbon cycling in forest soils through the turnover of their fine roots. In this study we aimed to calculate root turnover rates of common European forest tree species and to compare them with most frequently published values. Methods: We compiled available European data and applied various turnover rate calculation methods to the resulting database. We used Decision Matrix and Maximum-Minimum formula as suggested in the literature. Results: Mean turnover rates obtained by the combination of sequential coring and Decision Matrix were 0.86 yr−1 for Fagus sylvatica and 0.88 yr−1 for Picea abies when maximum biomass data were used for the calculation, and 1.11 yr−1 for both species when mean biomass data were used. Using mean biomass rather than maximum resulted in about 30 % higher values of root turnover. Using the Decision Matrix to calculate turnover rate doubled the rates when compared to the Maximum-Minimum formula. The Decision Matrix, however, makes use of more input information than the Maximum-Minimum formula. Conclusions: We propose that calculations using the Decision Matrix with mean biomass give the most reliable estimates of root turnover rates in European forests and should preferentially be used in models and C reporting.
Sammendrag
Vi har flere arter av honningsopp i Norge, og to av dem, skog- og hagehonningsopp, er svært aktive ute i skogen. Begge artene forårsaker innråte i trær, men kan også opptre mer aggressivt og drepe svekkede trær nokså raskt. Honningsopp er involvert i grantørke som i de senere årene har utviklet seg til det verre, trolig i takt med klimaendringer.
Sammendrag
The development of new tools able to select specific plant tissue is crucial for gene expression studies. During the last years, the use of laser microdissection, mainly tested on herbaceous plant tissue, has been found to be a useful technique for these purposes. This method is poorly tested on woody species, and so far no studies of gene expression have been applied on forest trees. For this reason the present work proposes the optimization of a functional protocol using laser microdissection pressure catapulting (LMPC) and real-time reverse transcription–polymerase chain reaction (RT-PCR) in bark stem tissue of Norway spruce (Picea abies). Bark tissue fragments were collected from Norway spruce trees and sliced with a cryostat. RNA was extracted from both whole cross-sections and microdissected bark cells. The feasibility of the method was confirmed by the amplification of the α-tubulin, an endogenous gene of P. abies, with efficiency comparable to that obtained from non-microdissected tissue. The proposed protocol, here adapted for bark tissue of woody species, represents a useful tool in a wide range of hosts that, unlike herbaceous plants, have scarcely been considered up to now.
Forfattere
Hugo Germain Denis Lachance Gervais Pelletier Carl Gunnar Fossdal Halvor Solheim Armand SeguinSammendrag
A 1149 bp genomic fragment corresponding to the 5' non-coding region of the PgD1 (Picea glauca Defensin 1) gene was cloned, characterized, and compared with all Arabidopsis thaliana defensin promoters. The cloned fragment was found to contain several motifs specific to defence or hormonal response, including a motif involved in the methyl jasmonate reponse, a fungal elicitor responsive element, and TC-rich repeat cis-acting element involved in defence and stress responsiveness. A functional analysis of the PgD1 promoter was performed using the uidA (GUS) reporter system in stably transformed Arabidopsis and white spruce plants. The PgD1 promoter was responsive to jasmonic acid (JA), to infection by fungus and to wounding. In transgenic spruce embryos, GUS staining was clearly restricted to the shoot apical meristem. In Arabidopsis, faint GUS coloration was observed in leaves and flowers and a strong blue colour was observed in guard cells and trichomes. Transgenic Arabidopsis plants expressing the PgD1::GUS construct were also infiltrated with the hemibiotrophic pathogen Pseudomonas syringae pv. tomato DC3000. It caused a suppression of defensin expression probably resulting from the antagonistic relationship between the pathogen-stimulated salicylic acid pathway and the jasmonic acid pathway. It is therefore concluded that the PgD1 promoter fragment cloned appears to contain most if not all the elements for proper PgD1 expression and that these elements are also recognized in Arabidopsis despite the phylogenetic and evolutionary differences that separates them.
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Nina TrandemSammendrag
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