Hyperaccumulators are plants that accumulate exceptionally high amounts of heavy metals (> 1% on dry mass basis) in their above- ground parts. Recently, such plants became of special interest due to the possibility of using them for remediation of heavy metal contaminated soils (phyto-extraction). Thlaspi caerulescens is the best known Zn hyperaccumulator and the only Cd accumulator identified so far. The light and dark phase of photosynthesis are studied at high concentrations of Zn and Cd. Simultaneous measu- rement of fluorescence parameters and activity of photosynthetic oxigen evolution will be performed. The nutrient uptake capacity is studied with increasing metal stress. We look for special adaptations in the photosynthetic apparatus and nutrient uptake mechanisms.