Effects of above-limit ground-level ozone concentrations on the health condition of the silver birch (Betula pendula Roth) assimilation apparatus within the period of 2009–2011

Effects of above-limit ground-level ozone concentrations on the health condition of the silver birch (Betula pendula Roth) assimilation apparatus was monitored using the method of study of changes in epicuticular waxes. These waxes are present on the surface of leaves and protect the plant (and, especially, its assimilation apparatus) against negative environmental effects. Studies were performed in a tree stand of the 2nd age category in altitudes ranging from 600 to 1,050 m in the Ore Mountains (Krušné hory in Czech). It was found out that, as compared with a control stand, the thickness of the wax epicuticular layer decreased with the increasing altitude while concentrations of the ground-level ozone increased. A visible damage of the assimilation apparatus was observed in localities with the highest concentrations of ground-level ozone. Here, not only an overall decrease in the amount of epicuticular waxes was observed but also a degradation of their structure. A statistical analysis of results proved that the loss of epicuticular waxes was significantly dependent on above-limit concentrations of ground-level ozone.