Geographic variation in the leaf essential oils of Juniperus cedrus Webb. & Berthol. from Madeira and the Canary Islands

Abstract

The volatile leaf oils of J. cedrus from Madeira, Gran Canaria, La Gomera, La Palma and Tenerife were analyzed and the compositions reported and compared with J. oxycedrus, France. The oil of J. cedrus from Madeira Island was moderately high in α-pinene (24.9%), limonene (10.9%), β-phellandrene (7.3%), δ-3-carene (5.6%), (E)-caryophyllene (4.3%), with considerable amounts of diterpenes: sandaracopimara-8(14),15-diene (2.8%), abietatriene (1.4%), iso- abienol (7.2%), nezukol (0.4%), sempervirol (0.6%), trans-totarol (8.6%), and trans-ferruginol (1.2%). In contrast, J. cedrus from the Canary Islands was very high in α-pinene (54.6 - 66.3%), with moderate amounts of β-pinene (2.2-3.3%), myrcene (3.6-5.9%), α- phellandrene (0.5-3.0%), β-phellandrene (4.1-13.1%), with little or no δ-3-carene (0.0-0.1%), and almost no diterpenes. The major geographic trend was the divergence of J. cedrus, Madeira, from the populations in the Canary Islands. The level of divergence of the Madeira population from the Canary Islands populations was comparable to the divergence of J. cedrus from J. oxycedrus, implying considerable evolutionary differences.