Volatiles from vegetative organs of the palaeoendemic resurrection plants Ramonda serbica Panc. and Ramonda nathaliae Panc. et Petrov.

GC and GC/MS analyses of the essential oils hydrodistilled separa- tely from fresh leaves and roots of Ramonda serbica and Ramonda nathaliae, together with diethyl ether extracts of their roots, enabled the identification of 82 constituents accounting for between 88.9 and 94.5 % of the oils and extrac- ted compounds. Although phenylacetaldehyde was one of the major contribu- tors (20.5-57.1 %) of all the oils, it was only a minor contributor to the ex- tracts. The latter were characterized by a large amount of squalene (R. serbica - - 36.0 %; R. nathaliae - 59.4%) and steroids (R. serbica - 27.4 %; R. nathaliae - - 14.1 %). Squalene was also the most abundant compound in R. nathaliae root oil (29.0 %), but was not detected in the corresponding R. serbica oil. While the root oils and extracts of both species contained comparable amounts of vo- latile fatty acids, there were significant differences in their contents in the oils hydrodistilled from the leaves of R. serbica and R. nathaliae (18.7 % and 0.6 %, respectively). The presented results provide the first insight into the unique sets of volatiles produced by these distinctive, closely related, relict taxa, which disclose their specific adaptive advantages.