Hyperaccumulator plants are able to tolerate extremely high concentrations of
metals/metalloids in the soil in which they grow and to accumulate high
concentrations in their shoots. To date, a total of 31 hyperaccumulator
plant species have been identified in the Balkans, the centre of diversity
and speciation in the European flora which is particularly rich in
ultramafic areas. A further 8 species have yet to be confirmed through
additional studies. Most of the 31 hyperaccumulator taxa (13 taxa or 41.9%)
are species of the genus Odontarrhena, all hyperaccumulating Ni, but
concentrations of this element above the hyperaccumulation threshold were
also found in the genera Bornmuellera and Noccaea (all Brassicaceae),
Orobanche (Orobanchaceae), Centaurea (Asteraceae) and Viola (Violaceae). The
existence of hyperaccumulators of Tl and Zn is of particular interest
because very few species worldwide hyperaccumulate these elements. Multiple
metal hyperaccumulation was found in Noccaea kovatsii, as the
hyperaccumulation of Zn was found in this species in addition to Ni, the
primary accumulated element. Metal hyperaccumulation is discussed in terms
of phylogenetic relationships and species distributions, with special
attention to their systematics, the detection and recognition of new
hyperaccumulating species and the possibilities for their future practical
applications in phytotechnologies.