STUDY OF INTERACTION OF IRON AND LEAD DURING THEIR UPTAKE PROCESS IN WHEAT ROOTS BY TOTAL-REFLECTION X-RAY-FLUORESCENCE SPECTROMETRY

Microwave assisted acidic digestion and total-reflection X-ray fluores cence spectrometry (TXRF) was used for the determination of lead and i ron in wheat roots cultured in CaSO4 solution, and treated with Pb(NO3 )(2) and Fe(III)-citrate or Fe(III)-EDTA under controlled conditions, respectively. It was established that lead has a stimulation effect on the iron uptake in the presence of Fe(III)-citrate. The lead uptake, however, is hardly influenced by iron independently from the complex f orming agents applied, To check the stability of the accumulated iron and lead constituents, some of the roots were washed with various solu tions and the removable iron and lead were also measured by TXRF, Thes e experiments indicate that the presence of lead results in higher sta bility of iron constituents in the root; however, iron does not have a ny effect on the lead constituents, the stabilities of which increase in the order Pb-citrate < Pb-(cell wall) < Pb-EDTA. (C) 1997 Elsevier Science B.V.