The Geography of Phytochemical Races

2.3 Europe 45
triacylglycerols from the two areas, however. The esters from both species were based
mainly (>95%) on four acids, palmitic (16:0), oleic (18:1∆ 9 ), linoleic (18:2∆ 9,12 ), and
α-linoleic(18:3∆ 9,12,15 ), but compositions differed in seeds from northern versus southern
sites. Thus, the proportion of linoleic acid in seeds of R. chamaemorus from northern
Finland (Lapland) was highest (P < 0.05) and that of α-linoleic lowest (P < 0.01). In
seeds of Empetrum from southern Finland, α-linoleic was present in the highest proportion
(P < 0.001) with linoleic present in the lowest proportion (P < 0.001).
The second example from Finland involves a study of variation in volatile compounds
in tansy (Tanacetum vulgare L.) by Keskitalo et al. (2001). In the introduction
to their paper, those authors reviewed the numerous uses to which tansy has
been put: fl avoring agent for foods, herbal remedy, anthelmintic, anti-infl ammatory
agent, as an agent against microorganisms, and as an insect repellent. They also
commented on the existence of several chemotypes throughout the plant’s wide distribution
in the Northern Hemisphere. The primary goal of their study was to select
lines of tansy that exhibit enhanced insecticidal properties to which end a detailed
study of Finnish populations was undertaken. An earlier study (Keskitalo et al.,
1998), using random amplifi ed polymorphic DNA (RAPDs), had documented the
level of genetic variation among 20 accessions. The two main groups that emerged
from that study were further distinguished by fl oral differences. The study of volatile
oil composition was undertaken to see if there was any correlation between the
microchemical data and the genetic patterns observed in the earlier study.
Twenty populations were sampled with plants from Hailuoto, at 65°00 N, representing
the northernmost site and material from Hanko, at 59°49 N, representing the
southernmost collection site (and, incidentally, the southernmost point of land in the
country). Five samples represented central Finland with the remainder originating
from the southern part. Fifty-fi ve compounds were detected by GC-MS analysis, 53
of which were identifi ed. The data obtained were subjected to complete linkage analysis,
which differentiated several clusters that corresponded moderately well with
geography. Genetic distance values derived from the RAPD data correlated well with
chemical distance values determined from the terpene data (r = 0.41, P < 0.0001).
The most commonly observed terpene was camphor [93] (see Fig. 2.24 for structures
93 and 94), whose concentration exceeded 18.5% in 13 of the genotypes, but
was present in less than 7.2% in the other seven. The highest levels approached 70%
in some groups with a low of 0.06% in one southern sample. The majority of highcamphor
genotypes occurred in central Finland, whereas those with little or low
amounts were observed in specimens from southern and southwestern Finland. This
fi nding is in agreement with an earlier study by Sorsa et al. (1968), who reported
higher levels of camphor in northern specimens as opposed to southern specimens,
where thujone [94] was the more prominent compound. In the present study, however,
thujone was not seen as a major component in southern specimens (it was a
major component in a single collection from central Finland).
An interesting dispersal scenario was described by the authors on the basis of the
similarity of southern Finnish chemotypes to chemotypes found in the Netherlands,
and other parts of Northern Europe. They suggest that tansy seeds, known to be common
components of shipping ballast (Jutila, 1996), may have been transported to