One hundred Norway spruce (Picea abies (L.) Karst.) clones (three ramets per clone) were analyzed for phloem phenol composition and concentration before and 10 days after wound inoculation with sterile malt agar. Fifty clones (Experiment 1) belonged to the same provenance, whereas the remaining clones (Experiment 2) belonged to five provenances from three geographic areas. In Experiment 2, two additional ramets from the same clones were mass inoculated with Ceratocystis polonica (Siem.) C. Moreau to quantify the resistance of each clone. Tree response to wound inoculations was characterized by increased catechin concentration in both experiments, accompanied by increases in astringin and decreases in piceid in Experiment 1. In both experiments, we observed a diverse group of phenolic compounds whose concentrations increased (catechin, astringin) or did not vary (taxifolin glucoside) in response to wound inoculations, whereas concentrations of a homogeneous group of stilbene compounds decreased (piceid) or did not vary (isorhapontin, unidentified stilbene). In Experiment 2, provenances from the alpine and Hercynian-Carpatic areas differed from provenances from the Baltic area with respect to the relative importance of these two groups of compounds, further indicating that the two groupings of phenolic compounds structure the Norway spruce populations. Eighty days after mass inoculation, the percentage of healthy sapwood, which was taken as a measure of tree resistance, indicated that clones from the Baltic area were less resistant to mass inoculations than clones from the alpine and Hercynian-Carpatic areas. We conclude that the degree of resistance of Norway spruce trees to mass inoculations with a bark beetle-associated fungus can be predicted based on the diversity of constitutive phloem phenols and the ability to induce phenol synthesis in response to wounding.
Quantitative traits and random amplified polymorphic DNA variations were investigated on the whole natural range of Norway spruce (Picea abies (L.) Karst.). Results showed that the species can be separated into two main groups (northern and central Europe) using both types of characters. Such spatial and geographical fragmentation of species natural range rarely occurs in conifers and is consistent with prolonged geographical isolation within two refugial zones located in distinct environmental conditions (Moscow area and east of central European mountains). Within each of these two infraspecific groups, we revealed an apparent uncoupling between quantitative traits (related to growth, phenology, and wood quality) and DNA. However, the combination of both molecular and quantitative traits information provided new insights about geographical patterns of variation: a dominant latitudinal gradient was found in the Baltico-Nordic domain contrasting markedly with the main eastwest migration expected from pollen data, while in central Europe, a noticeable longitudinal gradient was congruent with eastwest migration. The concordance and discrepancies between quantitative traits and DNA are discussed in terms of historical events in P. abies.
Summary -Genetic variability in the relationship between pilodyn pin penetration (an indirect measure of wood density) and stem girth of individual trees was assessed at three levels (provenance, family [half-sib]
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