Introduction

1. The response of the multiple hyperaccumulatorsThlaspi caerulescens, Thlaspi goesingense and the excluder plant Plantago major towards the radionuclide 238U A. Burger1, M. Weidinger1, W. Adlassnig1, N. Baumann2, T. Arnold2, N. Zöger3,I. Lichtscheidl1 • 1. University of Vienna, Cell Imaging and Ultrastructure Research, Althanstrasse 14, A-1090 Vienna, Austria, anna-burger11@hotmail.com • 2. Helmholtz-Zentrum Dresden-Rossendorf, 01314 Dresden, Germany • 3. Nuclear Engineering Seibersdorf GmbH, 2444 Seibersdorf Austria Introduction Conclusion • Uranium (U) is a naturallyoccuringradiotoxicandchemotoxicheavy metalandradionuclidewithimportantecologicimpact. Itcanlocallyreachseveralhundredsofmg kg-1 due tominingandmilling. Previousstudieshaveshownthat U alters plant growthanddevelopment. • Onlylittleinformationisavailable on U uptake. This workaimstostudy: • U uptakebyhyperaccumulatingandexcludingplants • Deposition of U in different plant organsandtissues • Macroscopiceffects of U on physiologicalparameters Resistantplantscansurvive in high U concentrations. Thlaspi absorbedandsurvivedupto 1 mSv dose rate duringtheexperiment. Plant growthisonlymoderatelyaffectedby U, especially in Plantago. U isratherevenlydistributedboth in therootand in theleaf but tendstoaccumulate in specifictissues. Principalcomponentanalasys (Fig.3) showedthat U tendstocorrelatewithFe, Na, Mg, but not withotherphysiologicallyimportantelements such asMn, Ca, K, P, Zn. EDX Results ICP-MS Results Plant Performance a b Root Leaf CC U U M C U E U a b Fig. 9. EDX-spectraobtainedfrom: (a) P. majorrootcrosssection in the SEM, C-cortex, CC-centralcylinder, 10 mM U (b) T. goesingenseleafcrosssection in the SEM, E-epidermis, M-mesophyll, 10 mMU a b M Fig.1. The total uranium content of the (a) root and (b) leaf tissue of three plant species Fig.4. Chlorophyll fluorescence in relationto U concentrationforthree different species Fig.10. The total uranium content in cross sections of the root (a) and leaf (b) by three species a b c a b Fig.11. The total uranium contentacross different root (a) and leaf (b) cells of T. caerulescens Fig.2. Uranium absorption in the mainorgans of (a) T. caerulescens, (b) T. goesingense, (c) P. major Fig.5. Root lengthofT. caerulescens, T. goesingenseand P. major Fig.6. LeaflengthofT. caerulescens, T. goesingenseand P. major a b Fig.12. The total uranium contentacross different root (a) and leaf (b) cells of T. goesingense a b Fig.8. Dry leafbiomassofT. caerulescens, T. goesingenseand P. major Fig.7. Dry rootbiomassofT. caerulescens, T. goesingense and P. major Fig.3. PrincipalComponent Analysis of the relative peakareas of 9 elementsfound in three plant species Fig.13. The total uranium contentacross different root (a) and leaf (b) cells of P. major Materials and Methods Cultivation Techniques Plant material Hyperaccumulators • Hydroponiccultivationwhithoutphosphorus, KH2PO4 was sprayedontotheleaves. • 6 different U concentrations (UO2(NO3)2·6 H2O) between 1 µM and 10 mM. • Coordinationandmobilization of U byaddition of citricacid. • Determination of U contentbydigestion in HNO3 + HClO4 and subsequent ICP-MS (Elan 9000, PerkinElmer). • Localization of U in sections of rootsandshootsby EDX (Philips XL20). • Determination of chlorophyllfluorescence , rootandleaflength, rootandleafbiomass. Ni/Cd/Cr Zn/Cd/Pb Thlaspi caerulescens, Ramingstein (AUT) Thlaspi goesingense, Ochsenriegel (AUT) Plantagomajor, former U miningarea (GER) Excluder References • Baker AJM, McGrath SP, Reeves RD, Smith JAC. 2000. Metalhyperaccumulator plants: a review of the ecology and physiology of a biological resource for phytoremediation of metal-polluted soils. Phytoremediation of Contaminated Soil and Water, Terry N and Baruelos GS (Eds.), CRC Press, Boca Katon, pp: 85-107. • Dushenkov S, 2002. Trends in phytoremediation of radionuclides. Plant and Soil, Vol. 249, No 1, pp. 167-175. • LarocheL., Henner P., Camilleri V., Morello M., Garnier-Laplace J.. Root uptake of uraniumby a higher plant model (Phaseolusvulgaris)-bioavailabilityfromsoilsolution. Radioprotection, Suppl. 1, vol. 40 (2005) S33-S39. • Vieweger K, Geipel G, Uranium accumulation and tolerance in Arabidopsis halleri under native stress hydroponic conditions. Environmental and Experimental Botany 69 (2010) 39-46. Acknowledgments We are grateful to Doz. Dr. O. Horak for providing seeds of Thlaspi plant species and Dr. Bachmann for his advice on the statistical analysis. We thank Prof. DI Dr. G. Hillebrand for the support throughout this project. We are also grateful to DI Dr. A. Vesely for scientific advice and help with analysis. We acknowledge the possibility to work in the Green House Facility of the University of Vienna and we thank the Gardeners of the Green House Facility. Our work was patlyfinanced by the EU Project UMBRELLA and by the ÖAD/APPEAR project BIOREM.