The leaf wax characteristics of Dryas octopetala and Saxifraga oppositifolia, collected from the high Arctic semi-desert of Svalbard, Norway (79 degrees N, 13 degrees E), were compared and differences in their wax composition related to winter snow cover. The leaf wax composition of the winter-green D. octopetala differed from that of the herbaceous S. oppositifolia in that high abundances of the triterpenoids, ursolic acid, oleanoic acid and uvaol, were observed in D. octopetala extracts but not in S. oppositifolia extracts. D. octopetala leaf waxes were consistently lower in n-alkanes and in n-alkanols compared to the leaf waxes of S. oppositifolia. Leaf waxes of both species from snow-free, wind-swept microsites had significantly higher abundances of n-alkanes than in those plants growing in adjacent, swale areas where snow accumulates in winter. It is hypothesized that this higher abundance of n-alkanes may be due to a response to a greater degree of dessication, lower temperatures and lower soil moisture experienced by plants on the snow-free ridge microsites during leaf expansion. In order to test whether these biochemical and anatomical attributes might change in response to short term alterations in winter climate, snow fences were erected on ridge sites. The wax attributes of ridge plants exposed to a single year of increased winter snow cover were examined and the n-alkane composition of leaf waxes were observed to be more like those of plants growing in adjacent swale areas than for those of ridge plants growing in unmanipulated areas. This shift in leaf wax composition implies that environmental differences during leaf development can have an influence on final leaf wax composition.
