Application of the sequential elution technique to determine Cd and Cu cellular location in Ulva lactuca linnaeus

The sequential elution technique, used to determine the cellular location o f metals in nonvascular plants, was adapted to the seaweed Ulva lactuca Lin naeus for the heavy metals Cu and Cd. The optimum conditions for the extrac tion of extracellular Cu and Cd were determined using specimens previously loaded with these metals. The best extracellular metal extraction media and the number of extracellular metal extraction steps obtained were the follo wing: Two steps (1 h + 40 min) in a filtered sea water-20 mM Ni solution fo r Cd and two steps in a filtered sea water-50 mM Co solution for Cu. To fin d these extraction conditions the extracellular metal extraction capacity o f the different media used as well as the alteration provoked in plasmalemm a permeability were compared. The concentrations of the incubation solution s of Cd and Cu that allowed reliable comparisons between the different extr acellular metal extraction media used were previously determined.