HYPERACCUMULATION, COMPLEXATION AND DISTRIBUTION OF NICKEL IN SEBERTIA-ACUMINATA

The nickel content in different parts of the hyperaccumulating tree Se bertia acuminata was analysed by atomic absorption spectroscopy. Nicke l was found to be mainly located in laticifers. The total nickel conte nt of a single mature tree was estimated to be 37 kg. By gel filtratio n and NMR spectroscopy, citric acid was unequivocally identified as co unter ion for about 40% of this metal present. Nitrate was assumed to be a further partner for a complete ionic balance. Phytochelatins were not found to be involved in nickel detoxification in Sebertia. The lo calization of nickel complexes inside the laticifers was demonstrated by light microscopy as well as by scanning electron microscopy in comb ination with an EDX system for the analysis of elements. A repellent e ffect of the plant sap was observed on the fruit fly Drosophila melano gaster indicating that in hyperaccumulating plants nickel functions as an agent to prevent predation. (C) 1997 Elsevier Science Ltd. All rig hts reserved.