Copper uptake in Typha latifolia as affected by iron and manganese plaque on the root surface

The effects of iron (Fe) and manganese (Mn) plaque on the accumulation of c opper (Cu) in Typha latifolia L. were investigated under laboratory conditi ons in nutrient solution cultures. Seedlings with and without Fe plaque on their roots, induced with 15 or 60 mug.mL(-1) Fe, were exposed to 0.04, 0.1 2, or 0.36 mug.mL(-1) Cu solutions, and seedlings with and without Mn plaqu e, induced with 15 or 60 mug.mL(-1) Mn, were exposed to 0.12 or 0.36 mug.mL (-1) Cu solutions for 24 days, respectively. In all cases, the amount and p roportion of Cu adsorbed on the root surface increased with a higher concen tration of Cu in the solutions. In the presence of Fe or Mn, T. latifolia a dsorbed more Cu and had a higher proportion of Cu on its roots, especially the roots with heavy Mn or Fe plaque. Although more Fe than Mn accumulated on the roots in the form of plaque, the Mn plaque adsorbed more Cu. The dat a suggest that root plaque can act as a Cu reservoir, depending on the amou nt of Fe or Mn on the roots and the amount of Cu in the environment.