ACCUMULATION AND TRANSLOCATION OF LEAD IN CUCUMBER PLANTS MONITORED BY GRAPHITE FURNACE ATOMIC ABSORPTION SPECTROMETRY

摘要

The lead concentration in different parts of cucumber plants, growing in ''lead-free'' and lead-contaminated nutrient solutions, was determined by the graphite furnace atomic absorption spectrometry technique after microwave-assisted acidic digestion of the dried plant parts. The lead accumulates first inion the roots, where its concentration can exceed 10 mg/g. In the upper parts of the plant (stem and leaves) the lead concentration is lower by about two orders of magnitude than it is iri the roots. The lead distribution within the plants shows a tendency to decrease with increasing leaf storage. An increment of the Pb(NO3)(2) concentration in the nutrient solution from 10(-8) to 10(-4) mol/dm(3) results in about 500 times higher lead concentration in the leaves. Nearly 20% of the deposited lead translocates from the contaminated lower stem part to the old leaves and to the new roots during the rerooting of a decapitated plant grown in lead-free nutrient solution. However, the new shoots which form during this period do not participate in this redistribution process. (C) 1995 Academic Press, Inc. [References: 6]