Studies on the behaviour of lead in wood binding of free and complexed Pb to xylem tissue.

The binding of lead to xylem tissue has been studied using an isolated segmentperfusion technique. The results show that free lead ions bind more readily to xylem tissue than does lead in the form of a lead-glycine complex. A small, but significant proportion of the applied lead moves laterally from wood to bark. Both binding and lateral movement of lead are shown to be time-dependant. The results are discussed in terms of using trees and the chemical analysis of their annual growth rings to date heavy metal pollution histories.