Selection effects of air pollution on gene pools of Norway spruce, European silver fir and European beech

The effects of industrial pollution on allelic and genotypic structures of Norway spruce, European silver fir and European beech were investigated by means of isozyme analysis. In a mixed Norway spruce-silver fir forest stand in an area heavily polluted by sulphur dioxide and heavy metals in the reg ion of Spis (eastern Slovakia), pairs of neighbouring damaged and apparentl y healthy trees were selected in two replicates (44 and 69 pairs in a heavi ly and moderately damaged stand, respectively). Pairwise sampling of trees with contrasting vitality was applied to reduce potential effects of site h eterogeneity on the vitality of sampled trees. No significant differences i n allelic and genotypic frequencies were found between sets of healthy and declining trees. There were differences in the single-locus heterozygositie s, but these were not consistent between the replicates. However, the set o f damaged trees exhibited higher levels of genetic multiplicity and diversi ty, possibly due to the deleterious effect of rare alleles under the condit ions of air pollution. Consequently, following the decline of pollutant-sen sitive trees, the remaining stand will be depleted of a part of alleles wit h unknown adaptive value to future selection pressures. (C). 2001 Published by Elsevier Science Ltd. All rights reserved.