Why does Thlaspi goesingense Hálácsy (Brassicaceae) Accumulate Metals?

Despite their great potential, a multitude of questions remain to be addressed before hyperaccumulators can be used to clean up contaminated sites. we used a scanning electron microscope and light microscopy to address the question how Tlaspi goesingense accumulates metals. Hyperaccumulation of nicekl by T. goesingense was confirmed: the recorded concentration was ten times beyond the treshold that defines a nickel hyperaccumulator. The pathogen/herbivore defence hypothesis can indirectly be confrimed because cuticular striations increased when the nickel concentration decreased. The large, elongated epidermis cells in T. goesingense indicate that metals are sequestered and immobilized because these cells correlated with elevated nickel concentrations. These cells are less frequently encountered in T. arvense, a non-hyperaccumulator. Exceptions were recorded in the leaves of the inflorescence axis: the nickel concentration here was relatively high but only a few elongated cells were present. The high amount of nickel and zinc in the plant confirms the metal tolerance of T. goesingense. The disposal-from-the-Plant-Body Theory can also be confirmed because the leaves of the leaves inflorescence axis, which are lost after flowering, accumulated high amounts of nickel. Detoxification is by disposal of nonessential plant organs. Other mechanisms of disposal are unlikely because no trichomes or other adaptations were recorde