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Publications

NIBIOs employees contribute to several hundred scientific articles and research reports every year. You can browse or search in our collection which contains references and links to these publications as well as other research and dissemination activities. The collection is continously updated with new and historical material.

2004

Abstract

Head-space sampling (HS) has been combined with enantioselective gas chromatography (GC) for the analysis of chiral and non-chiral monoterpenes present in the cortical tissues of five different Norway spruce clones. (1S)-()--Pinene, (1S,5S)-()sabinene, (1S)-()--pinene, and (4S)-()limonene dominated over (1R)-()--pinene, (1R,5R)-()-sabinene, (1R)-()--pinene, and (4R)-()-limonene.Results showed a large variation in the enantiomeric composition of cortical tissues between different clones. The development of HSGC greatly increased the speed of precise analyses of chiral monoterpenes in small samples and therefore offer excellent opportunities in studies on the ecophysiological and chemotaxomic roles of these chiral components

Abstract

Introduction: Survival and competitive successes of boreal forest trees depend on a balance between exploiting the full growing season and minimising frost injury through proper timing of hardening in autumn and dehardening in spring. Our research indicates that the female parents of Norway spruce adjust these timing events in their progeny according to the prevailing temperature conditions during sexual reproduction. Reproduction in a cold environment advances bud-set and cold acclimation in the autumn and dehardening and flushing in spring, whereas a warm reproductive environment delays these progeny traits by an unknown non-Mendelian mechanism. We are now looking for molecular mechanisms that can explain this “epigenetic” phenomenon. Material and methods: We have performed identical crosses with the same Norway spruce (Picea abies) parent, as discussed by Skrøppa & Johnsen (1994) and Johnsen et al. (1995), in combination with timed temperature treatments during shorter and longer periods from female meiosis, pollen tube growth, syngamy and embryogenesis and tested the progenies for bud-set and frost hardiness. We have followed the transcription of the spruce phytochromes PHYO, PHYP and PHYN and the class IV chitinase PaChi4 using Quantitative Multiplex Real-Time PCR. Results and conclusions: The effect of temperature on Adaptive properties is most likely a response to accumulated heat during embryogenesis and seed maturation. Our first attempt to look for a molecular mechanism has revealed that transcription of PHYO, PHYP and PHYN and the class IV chitinase PaChi4 (relative to alphaTubulin) all show higher transcription levels in progenies born under cold conditions than their full-sibs born under warmer conditions. This result is consistent with preliminary findings that methylation of cytosine in total DNA is higher in progenies reproduce under warm conditions than their colder full-sib counterparts. If these observations are related to methylation or other epigenetic effects, we may explain why progenies with a memory of a past time cold embryogenesis are more sensitive to short days than their full-sibs with a warmer embryonic history.

Abstract

No abstract has been registered