EN
Fluoride content and epicuticular wax condition in pedunculate oak tree leaves from a natural forest near a phosphogypsum dump and from a planted stand 2 km away from the dump (control) were investigated. The study indicated considerable differences in these parameters between the two localities. Increased fluoride content, accompanied by earlier and accelerated degradation of epicuticular crystalline wax on the stomatal rim of abaxial epidermis was observed in leaves from the first locality, and the most advanced stage of wax degradation was recorded only in the leaves from this site. The accelerated alterations are interpreted as possible negative effects of fluorides.