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How can plants deal with the relatively high toxic uranium?
Viehweger, K.; Geipel, G.;
Uranium is a widespread radioactive toxic heavy metal, released into the biosphere mostly by military purposes and nuclear industry. It is taken up by plant root systems and its chemical toxicity is much more dangerous than the radiological. Thus cell suspensions of rape (Brassica napus) revealed specific extracellular defence reactions after uranium exposure. These include characteristic pH-shifts of the culture medium caused by contact with the heavy metal. At the same time a transient release of fluorescent compounds from the cells occurred. These phytoalexins probably belong to the widespread group of flavonoids detected by HPLC and thin layer chromatography (TLC). They are able to interact with uranium, can alter the redox status of the metal and hence should protect the cell against this heavy metal poisoning. To gain an insight in these interactions time-resolved laser-induced fluorescence spectroscopy (TRLFS) and absorption spectroscopy were performed.
Former uranium mining sides in Eastern Germany were screened for uranium accumulating plants. An Arabidopsis halleri subspecies with high soil–plant transfer factors could be identified. Therefore a laboratory model system with this plant was established for investigations of uptake and sequestration of this metal. The initial characterisation of this experimental setup was carried out using “root-elongation-tests” to calculate the tolerance index and the measurement of some photosynthetic traits after uranium contact, respective.
Further research is under way to identify intracellular defence mechanisms, e.g. the involvement of glutathione and in this matter the formation of proteins possessing thiol groups (phytochelatins).
Keywords: Protein, plant cell, uranium
  • Invited lecture (Conferences)
    Kolloqiumsreihe des GTSC, 10.12.2008, Berkeley, USA

Publ.-Id: 11941 - Permalink