Plant selection and virological tests: Before effecting the collection procedure, heathy and infected plants of E. purpurea grown in the open field at the Herb Garden of Casola Valsenio were selected and labelled by visual inspection of their aerial parts. The infection by CMV was associated with symptoms on both leaves and flowers. The most characteristic symptoms are yellow mosaic, ring and line-patterns on crinkled and deformed leaves that drop prematurely. The flowers, which may be smaller than normal, show color breaking with white or pale stripes on red petals. Shortening of the internodes is also very common, giving the plant a bushy appearance known as stunting. In Italian environmental conditions, these symptoms are best visible in the summer. On the other hand, plants appeared symptom-free were collected as healthy material. Plant collection: About 3-4 Kg fresh aerial part materials (70% stems, 10% leaves and 20% flowers) of healthy E. purpurea plants were collected in June 2000 at almost the end of flowering. An equivalent quantity of CMV-infected plants (evaluated by DAS-ELISA) was also collected; the percentage of leaves in the infected infected was about 6.0% as due to CMV presence that caused the premature leaf drop.

The oil from healthy material was rich in germacrene D (57.8%) and was more abundant. The infected materials afforded a lower oil content and significant quantitative variations in the oil composition. In particular, the observed percentage of germacrene D (52.6%) was reduced as were other sesquiterpene hydrocarbons. These variations, tested to be significant for all the compound-class fractions and individual major components, were ascribed to the cucumber mosaic cucumovirus (CMV) infection, the only fixed-effect variable that might affect the oil composition.

The plant materials were collected for P1: 2900 m, Ait Akak, Oukaimden, Atlas Mts, Morocco, N. Achak, A. Romane and M. Mahroug, 3 trees, ns, 12/12/2003; P2, 2200 m, Plateau of Matat, Atlas Mts, N. Achak, A. Romane and M. Mahroug, 3 trees, ns, 18/03/2003; P3: 2000 m, Foret Islane, Oukaimden, Atlas Mts, N. Achak, A. Romane and M. Mahroug, 3 trees, ns,12/12/2003. A portion of the leaves from each of the three trees (per population) were air dried for 16 days at room temperature (ca. 22 &#8451) to produce the dried leaf samples.

The oil yields from fresh leaves showed on differences among geographical sources. Air dried leaves appeared to yield more oil at the highest elevation (1.03%, Ait Lkak, 2900 m) than lower sites (0.67%, Plateau of Matat, 2200 m; 0.57%, Foret Islane, 2000 m). The essential oils from each geographic site had very similar composition in fresh versus air dried leaves. The essential oils from provenance Ait Lkak and Plateau of Matat were very similar and characterized by a high sabinene content (21.2, 35.9%), in contrast to 10.% sabinene from the provenance Foret Islane. The oil from Foret Islane had a high delta-cadinene content with 12.7%, whereas Aik Akak and Plateau of Matat contained only 0.6 and 0.8%.