John Frampton

NMR studies on Fraser fir Abies fraseri (Pursh) Poir. lignins

Abstract The composition of mature, juvenile uninfested and juvenile infested Fraser fir wood (Rotholz) and the structures of lignins isolated from these woods were elucidated to verify differences between juvenile and mature wood and the effect of balsam woolly adelgid (BWA) infestation. Milled wood lignin (MWL) isolated from mature, juvenile and Rotholz wood were comprehensively characterized using heteronuclear multiple quantum coherence (HMQC) and quantitative 13C NMR techniques. The Rotholz wood was found to have ∼13% higher lignin content and more than five-fold the amount of galactans than that of the uninfested wood. Rotholz lignin possesses higher amounts of p-hydroxyphenyl units and aliphatic OH groups and a lower amount of alkyl-O-alkyl linkages and dibenzodioxocin moieties. The degree of condensation of the Rotholz lignin was rather similar to that of normal wood. Only small differences in the structure of mature and juvenile wood components were found.

Genetic variation and population structure in fraser fir ( Abies fraseri ): a microsatellite assessment of young trees

The island-like populations of Fraser fir (Abies fraseri (Pursh) Poir.) have been isolated since the end of the late-Wisconsinian glaciation on the highest peaks of the Southern Appalachian Mountains and therefore offer an opportu- nity to investigate the genetic dynamics of a long-fragmented forest tree species. An analysis of eight microsatellite markers isolated from Fraser fir found that the species was out of Hardy-Weinberg equilibrium, with a significant defi- ciency of heterozygosity and a high degree of inbreeding (FIS = 0.223) relative to other conifers, perhaps associated in part with the young life stage of the trees included in the analysis. The analysis detected a significant but small amount of genetic differentiation among Fraser fir populations (FST = 0.004) and revealed that the geographical and latitudinal distan- ces between populations, but not population area, were significantly correlated with their pairwise genetic differences. Both gene flow and postglacial migration history may have influenced the genetic architecture of the species. The results will be useful in the genetic conservation of Fraser fir, a species experiencing severe mortality following infestation by an exotic insect. Resume´ : Les populations de type insulaire de sapin de Fraser (Abies fraseri (Pursh) Poir.) sont demeurees isolees sur les plus hauts sommets du sud des Appalaches depuis la fin de la glaciation du Wisconsinien superieur. Elles representent donc une occasion detudier la dynamique des populations chez une espece forestiere fragmentee depuis longtemps. Lan- alyse de huit loci de microsatellites isoles chez le sapin de Fraser a permis de mettre en evidence que lespece etait en desequilibre dHardy-Weinberg, avec une deficience significative en heterozygotes et un niveau elevedendogamie (FIS = 0,223) par rapport aux autres coniferes. Ce resultat est possiblement relieen partie au fait que des arbres au stade juvenile ont eteinclus dans letude. Lanalyse a permis de detecter un niveau significatif mais faible de differenciation genetique parmi les populations de sapin de Fraser (FST = 0,004). Les distances geographiques et latitudinales separant les popula- tions, et non leurs regions dappartenance, etaient correlees significativement avec leurs differences genetiques par paire. Le flux genique ainsi que lhistoire migratoire post-glaciaire ont pu avoir une influence sur larchitecture genetique de lespece. Les resultats permettront de guider les efforts de conservation chez le sapin de Fraser, une espece qui connaoˆt une forte mortalitedue a une infestation causee par un insecte exotique. (Traduit par la Redaction)

Evolutionary history of two endemic Appalachian conifers revealed using microsatellite markers

Fraser fir (Abies fraseri [Pursh] Poir.) and intermediate fir (Abies balsamea [L.] Mill. var. phanerolepis Fern.) exist in small populations in the Appalachian highlands of the southeastern United States. We used ten nuclear microsatellite markers to quantify genetic variation within Fraser fir and intermediate fir, and to examine their evolutionary relationships with the widespread balsam fir (Abies balsamea [L.] Mill.). We found little genetic differentiation among these taxa, suggesting that Fraser fir might best be classified as a variety of balsam fir. The results further appear to reject the hypothesis that intermediate fir was of hybrid origin between two comparatively distantly related species. Low levels of genetic diversity suggest that intermediate fir and Fraser fir have undergone at least some genetic degradation since post-Pleistocene isolation. The results may prove important for in situ and ex situ gene conservation efforts for Fraser fir and intermediate fir, which are imperiled by an exotic insect and by global climate change.

Fraser Fir (Abies fraseri [Pursh] Poir.)

Fraser fir ( Abies fraseri [Pursh] Poir.) is a coniferous species native to the Southern Appalachian Mountains of the Eastern United States. Fraser fir has high economic and recreational value but is vulnerable to extinction due to introduced pests and global warming. Somatic embryogenesis may assist in the clonal production of Christmas trees and conservation of rare and valuable germplasm via cryopreservation. Improved protocols for embryogenic tissue initiation, culture capture and growth, somatic embryo development and maturation and cryogenic storage are presented based on the findings of Pullman (47:453–480, 2016).