The Geography of Phytochemical Races

2.3 Europe 49
be more prevalent in southern areas than in more northerly sites; thus, Greenland,
Iceland, and Norway had only two, fi ve, and one chemotype, respectively.
The north–south gradient was also evident in the concentration of the most
abundant chemotype, which was shown to consist of linaloöl [19] and its acetate.
Most frequent in Greenland, Iceland, and Norway (90–100%), it was present
in only 40% of plants collected in Scotland, and in only ca. 5% of plants
from southern sites. This fi nding paralleled the observations of Stahl-Biskup and
Laakso (1990) that a similar north–south trend exists in the oils of Thymus serpyllum
subspecies serpyllum and tanaensis in Finland. The opposite trend was
observed with γ-terpinene, which was present in southern populations but absent
from those from the northern sites.
Perhaps the most interesting aspect of this set of studies is the question posed
in the recent paper by Schmidt et al. (2004) and deals with the reality of the
patterns they observed. Is the polymorphism observed a result of the calculation
methods used in the study, neural network (NN), and multivariate statistical
analysis (MVA)? Would increased sampling result in a greater number of chemotypes?
It is entirely possible, of course, that the numbers obtained in this study are
a true refl ection of the biosynthetic capacities of the plants studied. The authors
concluded—and this is a point made elsewhere in this review—that “. . . for a
correct interpretation a good knowledge of the biosynthetic background of the
components is needed.”
2.3.12 Pinus uncinata (Pinaceae)
Pinus uncinata Ram. occurs discontinuously from the north of Spain to western
Switzerland, including populations in the Jura, the Vosges, and the Massif Central.
Although the taxonomy of this species is evidently open to some discussion,
Lauranson and Lebreton (1991) chose to set differences of opinion aside in their
study of the fl avonoid profi les of this pine. (References to the taxonomic literature
can be found in their paper.) For their fl avonoid analysis, twigs were collected
from at least 23 individuals at each of fi ve locations, two in the Pyrenees,
two in the Alps, and one in the Jura (Fig. 2.28). Site information, and relevant
results of their analyses, appears in Table 2.9. Procyanidin and prodelphinidin
(measured as the corresponding anthocyanidins, cyanidin [106], and delphinidin
[107], respectively) were found to occur in the same ratio in each population.
Following hydrolysis of the glycosidic fraction, three fl avonols were identifi ed,
kaempferol [108], quercetin [109], and isorhamnetin [110] (See Fig. 2.29 for
structures 106–110). Statistical analysis revealed that the fi ve populations could
be discriminated by their respective quercetin contents. The individuals from
each population were sorted into three categories: (1) less than 10% quercetin;
(2) 10–16% quercetin; and (3) more than 16% quercetin. Based upon the assumption
that the quercetin concentration was under one locus-two allele (A and a)
genetic control and that the three genotypes, AA, Aa, and aa, represented high,