The capacity to accumulate cadmium (Cd) and zinc (Zn) was compared in Thlaspi goesingense and four populations
of Thlaspi caerulescens. Two populations of T. caerulescens were grown in hydroponics at five concentrations of Cd.
In addition, plants were grown in pots containing compost in which three different concentrations of Cd and two
concentrations of Zn were added. A field trial was conducted to compare Zn and Cd uptake by three populations
of T. caerulescens on nine selected plots of the Woburn Market Garden Experiment (UK) which had been
contaminated to different degrees with heavy metals owing to past applications of sewage sludge. Results show that
the four populations of T. caerulescens had the same ability to hyperaccumulate Zn but were significantly different
in terms of Cd accumulation. Two populations of T. caerulescens from Southern France accumulated much more
Cd than the populations from Prayon (Belgium) and Whitesike (UK). Generally, uptake of Cd was not decreased
by increased concentrations of Zn in the substrate. These results indicate that the mechanisms of Cd and Zn
hyperaccumulation are not identical in this species. This is the first report of hyperaccumulation of Cd by T.
goesingense, but the growth of this species was markedly reduced by the large concentrations of Zn in the substrate.
Future work should focus on the differences between Cd and Zn uptake in hyperaccumulator plants at the species
and population level.
