En forêt boréale, les effets bénéfiques du passage du feu sur le substrat de germination ont souvent été liés à la présence de charbon et à son effet adsorbant sur les composés phénoliques qui inhibent la germination et la croissance des semis. L'objectif de la présente étude visait à mettre en évidence l'influence directe du charbon actif sur la germination et la croissance primaire des plantules de pin gris (Pinus banksiana Lamb.), une espèce très bien adaptée au feu. Quatre concentrations de charbon actif (0, 50, 100 et 150 % par rapport à la masse des semences) combinées à deux températures, respectivement 26 à 27 °C et 18 à 20 °C, ont été testées in vitro à une humidité constante dans des boîtes de Pétri. Les résultats montrent que l'ajout de charbon actif dans le milieu n'a pas eu d'effet significatif sur la germination des semences de pin gris. Pour ce qui est de la croissance des plantules cependant, le charbon actif exerce un effet inhibiteur, lorsque sa concentration dans le milieu est supérieure à 100 %. Une augmentation significative de la croissance a été uniquement observée seulement avec 50 % de charbon combiné à la température plus élevée (26–27 °C). Nous avons noté l'apparition de malformations à l'apex de la radicule particulièrement aux températures basses associées à des concentrations élevées de charbon actif dans le milieu.

In the boreal forest, the beneficial effect of wildfire on germination substrates has often been linked to the adsorption by charcoal of phenolic compounds detrimental for seedling germination and growth. Our goal was to show that active charcoal has direct positive effects on germination and early growth of jack pine (Pinus banksiana Lamb.) plantlets, a species well adapted to fire. Four concentrations of active charcoal (0%, 50%, 100%, and 150% seed mass) along with two temperatures (26–27 °C and 18–20 °C) were tested in vitro, in Petri dishes, under constant moisture conditions. Results showed that adding active charcoal to the substrate had no significant effect on jack pine seed germination but inhibited plantlet growth at concentrations over 100%. Significant growth increase was observed only with 50% charcoal at the highest temperature (26–27 °C). Deformities were noted at the apex of radicles, particularly with low temperatures and high levels of active charcoal in the substrate. ©2006 NRC Canada

In the present study we investigated the genetic structure and genetic diversity of Pinus heldreichii populations in Bulgaria using chloroplast microsatellite markers and terpene analysis. We were interested in addressing the following questions: (1) can population structuring in Bosnian pine be detected via chloroplast microsatellite markers; (2) are there differences in population differentiation as determined by terpenes and microsatellites; and (3) how are the patterns of size variant frequencies and geographical distances related. Four provenances were chosen throughout the species' range in Bulgaria. Following DNA extraction, chloroplast microsatellite (cpSSR) loci were surveyed using 6 primer pairs. Between 2 and 5 size variants were identified at each locus. A total of 16 size variants at the 6 loci were identified, 4 occurring at low frequencies. They were combined in 21 different haplotypes including 11 that were unique. AMOVA analysis revealed that 18.25% of the variation was found among populations, while 81.75% was expressed within populations. The cpSSR analysis divided Bosnian pine populations into two groups, the first represented by populations B, C and D located in the south and north-western part of the Pirin and Slavianka mountains, while the second group, represented by population A, is located in the north-eastern Pirin mountain. Terpene analysis revealed that on average, 59% of the monoterpene pool in P. heldreichii is accounted for by limonene (range 36-48%) followed by a-pinene (range 16-17%). The presence of two distinct groups (Pop-A, Pop-D and Pop-B, Pop-C) is more consistent with physical distances between populations. No significant correlation between genetic distance determined by chloroplast microsatellites analysis and chemotype distance determined by terpenes was observed. Our results suggest that the structural pattern of genetic diversity of cpDNA in Bosnian pine populations is the consequence of historical and biogeographical processes. © 2004 Elsevier Ltd. All rights reserved.

In this study we investigated the genetic structure and diversity of jack pine populations in Quebec using chloroplast microsatellite markers. Six cpSSR loci were used to screen 15 Pinus banksiana populations from an economically important region of the boreal zone. The main objective was to quantify the variation within and among populations and to relate this to their geographic pattern. From 3 to 6 size variants were identified at each locus. A total of 29 size variants at the six loci were identified and 5 of the size variants occurred infrequently. The size variants were combined into 87 different haplotypes, of which 49 were unique. The AMOVA analysis revealed that 10.96% of the variation was distributed between populations and 89.04% within populations. Cluster analysis divided the studied populations into two large groups, one from north-western Quebec and the second from eastern Quebec. These results suggest that the genetic structure of the studied jack pine populations is the result of interactions between historical post-glacial migrations and climate-disturbance structuring factors.