J. Phys. IV France 107 (2003) 613
EDTA reduces the physiological damage of lead on cardoon plants grown hydroponicallyJ. Hernandez-Allica1, O. Barrutia2, J.M. Becerril2 and C. Garbisu1
1 NEIKER, Basque Institute of Agricultural Research and Development, Department of Agrosystems and Animal Production, ci Berreaga 1, 48160 Derio, Spain
2 Department of Plant Biology and Ecology, University ofthe Basque Country, P. O. Box 644, 48080 Bilbao, Spain
Cardoon seedlings (Cynara cardunculus L.) were grown hydroponically in nutrient solution and exposed to lead (Pb 2+: ImM) in the presence of a range of different EDTA concentrations (EDTANa 2: 0, 0.5, 1 or 2mM). Analyses were performed to establish whether the coordination of Pb 2+ transport by EDTA enhances the mobility of this metal within the plant and to determine the toxic effects of these treatments during a phytoextraction process. Net photosynthesis, transpiration rate and stomatal conductance decreased dramatically in plants treated with Pb 2+ or Pb-EDTA at doses below 1 mM. ln these treatments, most of the Pb 2+ accumulated in the roots, alld only a very low amount of it was translocated to the shoots. Increasing the EDTA doses up to Pb 2+ equimolarity, increased the Pb 2+ shoot content more than 10-fold without any physiological evidence of toxicity. The treatment with higher doses of EDTA (Pb 2+ 1 mM + EDTA 2 mM) did not show toxicity symptoms, but the Pb 2+ concentration in the aboveground tissues decreased when compared with the equimolar treatment. The interaction with the absorption of some essential cations such as Ca 2+ and phytotoxicity on chelated-assisted phytoextraction is discussed.
© EDP Sciences 2003