ORIGINAL ARTICLE Robert L. Wolff ? Bernard Comps ? Anne M. Marpeau Laurent G. Deluc Taxonomy of Pinus species based on the seed oil fatty acid compositions Received: 5 June 1997 / Accepted: 17 August 1997 AbstractmThe fatty acid compositions of the seed oils from ten pine species have been established by capillary gas- liquid chromatography of the methyl esters. With regard to either normal fatty acids or D5-olefinic acids, the general pattern of fatty acids did not differ from that of other pine seed oils reported previously. The main fatty acid was linoleic (9,12±18:2) acid (44.4±57.1%), followed by either oleic (9±18:1) acid (13.4±24.5%) or pinolenic (5,9,12±18:3) acid (1.5±25.2%). When applying multivariate analyses to the chemometric data (13 variables) of 49 pine species (ca. 40% of the living pine species), it was possible to distin- guish between several sections: Pinea, Longifolia, Halepen- sis, Ponderosa-Banksiana, Sylvestris, and Cembra. The latter section was clearly divided into two sub-groups. A few species that presented a low overall content of D5- olefinic acids, and that grow in warm-temperate regions, were isolated from the bulk of other pine species. It is hypothesized that D5-olefinic acids might be related to cold-acclimation. Key wordsmFatty acid composition ? D5-olefinic acids ? Pine seed oil ? Taxonomy Introduction Gymnosperm seed lipids are characterized by the presence of peculiar fatty acids containing a D5-ethylenic bond arranged in a nonmethylene interrupted manner, frequently referred to as D5-olefinic acids or D5-unsaturated poly- methylene-interrupted fatty acids, with 18 or 20 carbon atoms, that are otherwise seldom encountered in Angios- perms. These acids have the structures 5,9±18:2 (taxoleic), 5,9,12±18:3 (pinolenic), 5,9,12,15±18:4 (coniferonic), 5,11±20:2, 5,11,14±20:3 (sciadonic), and 5,11,14,17±20:4 (juniperonic) (Takagi and Itabashi 1982; Berdeaux and Wolff 1996). A seventh D5-olefinic acid, 5,11±18:2 acid, has also been tentatively identified in a few rare Gymnos- perm species (Takagi and Itabashi 1982). For more than one hundred species analyzed (Takagi and Itabashi 1982; Wolff and Bayard 1995; Imbs and Pham 1996; Wolff et al. 1996, 1997c, e; Wolff and Marpeau 1997; this study), it was observed that the seed lipids from all species, with no exceptions, contain some of these fatty acids. Their sum may vary from a low of 0.8% (in Pinus edulis, Wolff and Marpeau 1997) to a high of 33.6% (in Larix sibirica, Wolff 1997), depending on the species. The latter value is appar- ently imposed by the fact that D5-olefinic acids are almost exclusively esterified to the sn-3 position of triacylglycerols (Wolff et al. 1997d), and consequently, they cannot be higher than one-third of total fatty acids. At approximately the same time, Wolff et al. (1996) observed that 9,12,15±18:3 (a-linolenic) acid allowed dis- tinction between two groups of conifer families (Pinaceae and Taxaceae on the one hand, Taxodiaceae and Cupressa- ceae on the other hand), while Imbs and Pham (1996) noted that the seed fatty acid compositions of Pinaceae could be used to separate this family from all other Gymnosperms. Later, Wolff et al. (1997e) processed the fatty acid compo- sitions of 82 conifer species through multivariate analyses, and they were able to clearly individualize the four families Pinaceae, Taxaceae, Taxodiaceae, and Cupressaceae. More- over, they could divide Pinaceae into the main genera, Pinus (including Tsuga and Pseudotsuga), Larix plus Picea, Abies and Cedrus. More recently Wolff et al. (1997c) showed that a clear-cut distinction could be estab- lished between pine species from the Ponderosa-Banksiana and Halepensis sections (both from the Pinus sub-genus), R.L. Wolff ( ) ISTAB, Laboratoire de Lipochimie Alimentaire, Universite  Bordeaux 1, Avenue des Faculte Âs, F-33405 Talence cedex, France Fax: 33 05 56 37 03 36 B. Comps Laboratoire d'Ecologie Ge Âne Âtique, Universite  Bordeaux 1, Avenue des Faculte Âs, F-33405 Talence cedex, France A.M. Marpeau ? L.G. Deluc Laboratoire de Physiologie Cellulaire Ve Âge Âtale, Universite  Bordeaux 1, Avenue des Faculte Âs, F-33405 Talence cedex, France Trees (1997) 12: 113 ±118 Ó Springer-Verlag 1997