CONTENTS AND ENANTIOMERIC COMPOSITIONS OF MONOTERPENE HYDROCARBONS INXYLEM-OLEORESINS FROM 4 PINUS SPECIES GROWING IN CUBA - COMPARISON OFTREES UNATTACKED AND ATTACKED BY DIORYCTRIA-HORNEANA

Monoterpene hydrocarbons from the xylem oleoresins of Pinus tropicalis , P. caribaea var. caribaea, P. cubensis and P. maestrensis growing in Cuba were investigated. A large number of oleoresin samples from tree s, attacked and unattacked by the moth Dioryctria horneana, as well as from trees growing in different localities, were analyzed. In each sa mple, the relative amounts of the volatiles and the enantiomeric compo sitions of six chiral monoterpene hydrocarbons were determined using a two-dimensional gas chromatographic (2D-GC) system. The GC-data were evaluated using two methods for multivariate data analysis, PCA (princ ipal components analysis) and PLS-DA (projections to latent structures -discriminant analysis). PC-plots based on the relative amounts of the monoterpenes present in the volatile oleoresin fractions analyzed, sh owed that P. tropicalis and P. cubensis formed one group, separated fr om P. caribaea, while pines belonging to the species, P. maestrensis w ere found in both groups. The species P. tropicalis and P. maestrensis , both of which are resistant to D. horneana, and the subgroups within the species P. caribaea and P. cubensis, that had not been attacked b y D. horneana, showed no signs of constituting a chemical subgroup. No significant difference was found between the attacked and the unattac ked P. cubensis trees. In P. caribaea, on the other hand, the composit ion of volatiles in attacked trees was significantly different from th at in unattacked trees. However, an influence of monoterpenes on the o viposition of D. horneana was not proved.