CHEMOTAXONOMIC DIFFERENTIATION OF CONIFER FAMILIES AND GENERA BASED ON THE SEED OIL FATTY-ACID COMPOSITIONS - MULTIVARIATE ANALYSES

The fatty acid compositions of seed oils from 34 conifer species, main ly Pinaceae and secondarily Cupressaceae, have been determined by gas- liquid chromatography of the methyl esters. As noted in earlier studie s, these oils were characterized by the presence of several Delta 5-ol efinic acids, i.e., 5,9-18:2, 5,9,12-18:3, 5,9,12,15-18:4, 5,11-20:2, 5,11,14-20:3, and 5,11,14,17-20:4 acids, in addition to the more commo n saturated, oleic, linoleic and alpha-linolenic acids. Based on these fatty acid compositions, and on those established in earlier systemat ic studies (totalling 82 species), we established a chemotaxonomic gro uping of the main conifer families, i.e., of the Pinaceae, Taxodiaceae , Cupressaceae, and Taxaceae. This was achieved using multivariate ana lyses (principal component analysis and discriminant analysis). The fa tty acids that discriminate best in this classification are the 5,11,1 4,17-20:4, 9,12,15-18:3 and 5,9,12-18:3 acids. Moreover, it was possib le to differentiate between several genera of the Pinaceae: Pinus (inc luding Tsuga and Pseudotsuga), Abies, Cedrus, and Picea plus Larix, re presented quite distinct groups. Other fatty acids such as oleic, lino leic, and 5,9-18:2 acids were also important for this purpose. The fat ty acid compositions, and particularly the Delta 5-olefinic acid conte nts of conifer seed oils, may thus be applied to the chemosystematic d istinction among conifer families as well as genera of the Pinaceae.