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L. Llorens et al. / Biochemical Systematics and Ecology 56 (2014) 246e254 251

Table 3 (continued )
Localities Bosnia 1 Bosnia 2 Sicily Ibiza Valencia Majorca
(Konnic/ (Borci/ (Marettimo) (Balearic (Spain) (Balearic
Spiljani) Bjelasnica) Islands) Islands)
Oxygenated monoterpenes (no phenolic) 3.3 4.8 3.8 3.1 2.5 4.6 10.7 4.2 4.6 2.9 1.2 2.8 15.1 9.4 14.7 0.4 0.6 1.1
Oxygenated monoterpenes (phenolic) 21.4 19.3 14.1 38.4 36.4 18.3 25.8 16.5 25.8 42.3 36.8 30.4 19.7 19.7 2.5 26.4 30.3 23.4
Sesquiterpene compounds 4.9 6.2 5.5 8.8 5.9 5.2 21.5 32.9 27.6 24.2 44.5 31.2 19.5 14.6 15.4 65.3 63.2 67.0
Sesquiterpene hydrocarbons 2.4 3.6 3.3 5.1 2.8 2.7 18.2 29.3 21.8 20.2 33.9 23.8 8.2 6.8 7.9 49.6 54.0 57.0
Oxygenated sesquiterpenes 2.5 2.6 2.2 3.7 3.1 2.5 3.3 3.6 5.8 4.0 10.6 7.4 11.3 7.8 7.5 15.7 9.2 10.0
Others compounds 1.1 1.6 0.9 2.4 3.4 1.4 2.2 1.4 0.6 1.1 0.3 1.0 0.4 0.7 0.5 0.5 0.1 0.6
Total 99.9 99.9 99.7 98.7 98.6 99.0 98.0 98.8 98.6 97.0 93.8 95.1 99.3 99.7 98.0 94.2 94.2 92.8
a KIE: Kovats (retention) index, experimentally determined, relative to C7eC24 n-alkanes on the ZB-5 column.
b
KIL: Kovats (retention) index, literature data (Adams, 2007).
3.2. Essential oil distribution

Discriminant analysis (LDA) was performed to develop a model of the distribution of component oils on the basis of
locality.
The first two factors explained 97% of the variability. Prior to this analysis the number of compounds had been reduced
based on correlation coefficients >0.95. The Majorca populations were found to be highly correlated with positive values of
the first factor (F1), whereas the Bosnio-Herzegovinian and Valencia populations were correlated with negative values of this
factor. Populations from Ibiza and Sicily were significantly correlated with positive and negative values of the second (F2)
factor, respectively (Fig. 3).
In the F1 discriminant function, b-bisabolene, carvacrol and germacrene-D were the major compounds differentiating the
populations of Majorca, Ibiza and Sicily from those of Bosnia and Valencia. Caryophyllene and g-terpinene were the principal
compounds differentiating the Ibiza and Sicily populations (function F2). The distribution plot gives four groups characterized
by a combination of five monoterpenes and three sesquiterpenes. The compounds b-bisabolene, carvacrol, g-terpinene, p-
cymene, 1-terpinen 4- ol, and camphene were the only components enabling statistically significant (P < 0.05) differentiation
of the two chemotypes (Table 4).
The chemical distances between the Ibiza and Sicilian populations were principally determined by the presence and
concentration of p-cymene, thymol and carvacrol.

3.3. Ecological factors affecting chemical variability

Although there was no statistically significant variation in the monoterpenes among the chemotypes, two chemotypes
were clearly spatially segregated in relation to a complex of environmental factors (climate and soils). The sesquiterpene
chemotype was confined to high altitude areas, in limestone rock crevices having an elevated ombrothermic index value and
low values for the thermicity and continentality indices (Tables 1 and 2). In contrast, the aromatic monoterpene chemotype
occupied habitats that are wet during summer, and have a high Jacob index and deeper soils. These conditions are also related
to the occurrence of non-phenolic chemotypes of Thymus vulgaris L. (Granger and Passet, 1973; Thompson et al., 2003).

Fig. 2. Variability of two principal components groups of T. richardi essential oils (monoterpenes and sesquiterpenes) in the studied populations (mean values,
% ± s.e).