Chemotaxonomic Considerations of the n-Alkane Composition in Pinus heldreichii, P. nigra, and P. peuce.

The n-alkane composition in the leaf cuticular waxes of natural populations of Bosnian pine (Pinus heldreichii), Austrian pine (P. nigra), and Macedonian pine (P. peuce) was compared for the first time. The range of n-alkanes was wider in P. nigra (C16  - C33 ) than in P. heldreichii and P. peuce (C18  - C33 ). Species also diverged in abundance and range of dominant n-alkanes (P. heldreichii: C23 , C27 , and C25 ; P. nigra: C25 , C27 , C29 , and C23 ; P. peuce: C29 , C25 , C27 , and C23 ). Multivariate statistical analyses (PCA, DA, and CA) generally pointed out separation of populations of P. nigra from populations of P. heldreichii and P. peuce (which were, to a greater or lesser extent, separated too). However, position of these species on the basis of n-alkane composition was in accordance neither with infrageneric classification nor with recent molecular and terpene investigations.

Terpenes as Useful Markers in Differentiation of Natural Populations of Relict Pines Pinus heldreichii, P. nigra, and P. peuce.

Comparative analysis of terpene diversity and differentiation of relict pines Pinus heldreichii, P. nigra, and P. peuce from the central Balkans was performed at the population level. Multivariate statistical analyses showed that the composition of needle terpenes reflects clear divergence among the pine species from different subgenera: P. peuce (subgenus Strobus) vs. P. nigra and P. heldreichii (subgenus Pinus). In addition, despite the described morphological similarities and the fact that P. nigra and P. heldreichii may spontaneously hybridize, our results indicated differentiation of their populations naturally growing in the same area. In accordance with recently proposed concept of 'flavonic evolution' in the genus Pinus, we assumed that the terpene profile of soft pine P. peuce, defined by high amounts of six monoterpenes, is more basal than those of hard pines P. nigra and P. heldreichii, which were characterized by high content levels of mainly sesquiterpenes. In order to establish precise positions of P. heldreichii, P. nigra and P. peuce within the taxonomic and phylogenetic tree, as well as develop suitable conservation strategies and future breeding efforts, it is necessary to perform additional morphological, biochemical, and genetic studies.