Chelated lead transport in Chamaecytisus proliferus (L.f.) link ssp proliferus var. palmensis (H. Christ):: an ultrastructural study

Chamaecytisus palmensis plants growing in hydroponic culture were exposed to Pb(NO3)(2), with and without the addition of the chelating agents H-EDTA and EDTA. for 1 week. Subsequently lead uptake was quantified in treated materials by flame atomic absorption spectrometry. Unchelated lead accumulated predominantly in root tissue, while lead chelated with either H-EDTA or EDTA was taken up principally by the shoots. With transmission electron microscopy, ultrastructural observations were carried out on ultra-thin sections derived from lead-treated C. palmensis tissues. Unchelated lead was found in cell walls. bacteroids and mitochondria in root nodule tissue, and in middle lamellae and intercellular spaces in root tissues. In roots. chelated lead was found in mitochondria. and in shoot tissues it was found in chloroplasts. pit membranes, and plasmodesmata. (C) 2001 Elsevier Science Ireland Ltd. All rights reserved.