Structural changes in needle epicuticular waxes of Balkan Abies species in relation to natural weathering

This study represents the first survey of the structural changes of needle epicuticular waxes of Abies alba Mill., A. x borisii-regis Mattf. and A. cephalonica Loudon in relation to natural weathering. In all three studied species, epicuticular wax on the adaxial surface of the needles was in the form of granules, whose amount increased with age of needles, so they were most prominent on the oldest needles. The main wax crystalloids on the abaxial needle surfaces were tubules with a tendency to concentrate within the stomatal complexes and between them in the stomatal rows. As the tubules aged they generally tended to agglomerate and fuse, forming amorphous wax crusts. Although we did not find differences in the micromorphology types of epicuticular wax among the examined species, both the tendency of the amount of granules to increase and the degree of degradation of tubules into amorphous crusts as the result of the natural aging process were well-documented.