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18 M. Sajewicz et al.

Basic qualitative features of the composition of the volatile fractions origirtating from sagę species coilected in 2007 and 2008 and isolated by use of the same experimental technique are quite similar, as is readily apparent from comparison of the chromatograms given in Figs 1-5. It should, how-ever, also be added that the pairs of chromatograms for 2007 and 2008 are not identical, even though ałl the laboratory conditions were kept exactly the same. One important difference between the two sets of plant materiał is the different harvesting times (August 2007 and October 2008). Another fac-tor certainly resulting in a difference is the unavoidable weather difference between the two gro w mg seasons compared.

Analogous conclusions can be drawn from quantitative comparison of the seasonal yields of voiatile compounds from the same sagę species (Tables ll-Vl). Although these yields are often quite similar, the discrepan-cies —occasionally quite substantial—cannot be regarded as an exception ei-ther.

There is, however, one firm similarity between the volatile fractions ob-tained from the plants harvested in 2007 and 2008— the consistent presence in (or absence from) the sagę species of the components first described as chemotaxonomic marker and advice compounds [14]. Thus for S. laoanduli-folia, in both growing seasons the presence of p-myrcene as chemotax-onomic marker and P-trwis-ocimene and thujone as chemotaxonomic advice compounds was confirmed. With S. staminea the presence of thujenone, and with S. hians and S. triloba the presence of thujone as respective chemotax-onomic advice compounds was shown. With S. nemorosa, the absence of these compounds was also confirmed. It thus seems that chemotaxonomy of the sagę species can be founded on the compounds in the volatile sagę frac-tion with the confirmed property of repeatable chemotaxonomic markers and advice compounds.

Conclusions

The following conclusions can be drawn from the results of this study:

•    Most efficient isolation of the volatile constituents of the five different sagę species was achieved by head-space gas chromatography at

70°C.

•    Despite seasonal differences in the quantitative composition of the volatile compounds derived from the five different sagę species harvested in the two different growing seasons, it seems that the consistent presence or absence of chemotaxonomic markers and ad-vice compounds in some sagę species can be regarded as useful for chemotaxonomic purposes with these particular species.