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INDUCED CHEMICAL DEFENSES IN CONIFERS" BIOCHEMICAL AND MOLECULAR APPROACHES TO STUDYING THEIR FUNCTION Axel Schmidt, l* Gazmend Zeneli, 1 Ari M. Hietala, 2 Carl G. Fossdal, 2 Paal Krokene,... more
INDUCED CHEMICAL DEFENSES IN CONIFERS" BIOCHEMICAL AND MOLECULAR APPROACHES TO STUDYING THEIR FUNCTION Axel Schmidt, l* Gazmend Zeneli, 1 Ari M. Hietala, 2 Carl G. Fossdal, 2 Paal Krokene, 2 Erik Christiansen 2 and Jonathan Gershenzon!/Max Planck Institute for Chemical Ecology Hans-KnOll Strasse 8 D-07745 Jena, Germany 2Norwegian Forest Research Institute (Skogforsk) Hogskoleveien 12 N-1432 As, Norway* Author for correspondence, e-mail: aschmidt@ ice. mpg. de ...
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Predicted increases in the frequency and duration of drought are expected to negatively affect tree vitality, but we know little about how water shortage will influence needle anatomy and thereby the trees'... more
Predicted increases in the frequency and duration of drought are expected to negatively affect tree vitality, but we know little about how water shortage will influence needle anatomy and thereby the trees' photosynthetic and hydraulic capacity. In this study, we evaluated anatomical changes in sun and shade needles of 20-year-old Norway spruce trees exposed to artificial drought stress. Canopy position was found to be important for needle structure, as sun needles had significantly higher values than shade needles for all anatomical traits (i.e., cross-sectional needle area, number of tracheids in needle, needle hydraulic conductivity, and tracheid lumen area), except proportion of xylem area per cross-sectional needle area. In sun needles, drought reduced all trait values by 10-40%, whereas in shade needles, only tracheid maximum diameter was reduced by drought. Due to the relatively weaker response of shade needles than sun needles in drought-stressed trees, the difference between the two needle types was reduced by 25% in the drought-stressed trees compared to the control trees. The observed changes in needle anatomy provide new understanding of how Norway spruce adapts to drought stress and may improve predictions of how forests will respond to global climate change.
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Using a simple temperature-driven multistage threshold developmental model, we analyse the impact of climate change on the life cycle dynamics of the spruce bark beetle Ips typographus. The completion of a full reproductive second... more
Using a simple temperature-driven multistage threshold developmental model, we analyse the impact of climate change on the life cycle dynamics of the spruce bark beetle Ips typographus. The completion of a full reproductive second generation within a single year (bivoltinism) might increase the risk of devastating bark beetle outbreaks. A network of more than 300 climate stations, comprising time series of air temperatures both observed as well as simulated using regional climate models, is exploited on the country scale. It is shown that current conditions strongly favor univoltine behavior, whereas climate scenarios predict almost strictly bivoltine behavior for southern Norway in 2071-2100. The dynamics of this threshold phenomenon is investigated in detail. Using a logistic regression, the impact of regional warming can be described as a northward movement of bivoltinism by some 600 kilometres. Thus, the risk for Norway spruce infestations in Scandinavia may be drastically incre...
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Pheromone communication systems have a reliable signal with a restricted window of amounts and ratios released and perceived. We propose a model based on a Gaussian response profile that allows a quantification of the response peak... more
Pheromone communication systems have a reliable signal with a restricted window of amounts and ratios released and perceived. We propose a model based on a Gaussian response profile that allows a quantification of the response peak (location of optimum) and a measure of the peak width (response window). Interpreting the Gaussian curve, fitted by nonlinear regression (NLR), as a standard normal distribution, the peak location equals the mean (it) and the window width equals 2 x the standard deviation (2sigma). The NLR procedure can provide an objective measure for both peak location and width for a wide range of data sets. Four empirical data sets as well as 10 literature data sets were analyzed. The double-spined spruce engraver, Ips duplicatus, was field tested in four populations to find the optimum proportion for attraction to the two male aggregation pheromone components, ipsdienol (Id) and (E)-myrcenol(EM), ranging from 0 to 100% of Id. Tests in Norway and the Czech Republic co...
Research Interests: Chemical Ecology, Pheromones, Chemical, Czech Republic, Communication System, and 18 moreBiological Sciences, Environmental Sciences, Standard Deviation, Maize, Nonlinear Regression, Female, Animals, Male, Chemotaxis, CHEMICAL SCIENCES, Beetles, Bark Beetle, Theoretical Models, Sex Pheromone, Inner Mongolia, Moths, Curve fitting, and Normal Distribution
Due to the great economic losses caused by the root and butt-rot pathogen Heterobasidion annosum (Ha), development of efficient control measures are warranted. H. annosum a necrotroph colonize the Norway spruce from inside and is... more
Due to the great economic losses caused by the root and butt-rot pathogen Heterobasidion annosum (Ha), development of efficient control measures are warranted. H. annosum a necrotroph colonize the Norway spruce from inside and is responsible for 100s of millions of Euros losses annually. Considerable clonal variation has been recorded for Norway spruce in resistance towards H. annosum, but the defence mechanisms contributing to host resistance remain poorly understood. Less susceptible clones appear to have an efficient ...
Abstract We monitored the effects of the drought stress on 20-year old clones of Norway spruce (Picea abies) by using a range of instrumental methods. On two experimental plots (Hoxmark, Norway, 59 40'14" N, 10 47'36"... more
Abstract We monitored the effects of the drought stress on 20-year old clones of Norway spruce (Picea abies) by using a range of instrumental methods. On two experimental plots (Hoxmark, Norway, 59 40'14" N, 10 47'36" E) the drought was induced in a period ...
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Research Interests: Plant Biology, Ecology, Plant diseases, Tree Physiology, Tree, and 4 moreTrees, Forestry Sciences, Picea, and Ascomycota
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Research Interests: Phytochemistry, Biological Sciences, Norway, Plant diseases, Animals, and 13 moreTerpenes, CHEMICAL SCIENCES, Beetles, Bark Beetle, Ips typographus, Picea, Visual Quality Inspection Systems, Gas Chromatography/mass Spectrometry, Picea abies, Norway Spruce, Monoterpenes, Methyl Jasmonate, and Ascomycota
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Constitutive and inducible terpene production is involved in conifer resistance against bark beetles and their associated fungi. In this study 72 Norway spruce.