Barley (Hordeum vulgare L.) plants were grown in nutrient solutions containing the chelating agent, DTPA. The experiments replicated those reported in the preceding paper in which EDTA was the chelating agent used. The concentrations of all the chemical species of metals were stimulated using the program NUTRIENT. The concentrations of DTPA used were chosen to give a similar range of complexation as used in the EDTA experiments. The effect of complexation by DTPA on the uptakes of the metal ions Fe3+, Mn2+, Cu2+, and Zn2+ and on plant growth were sufficiently different from those with EDTA to indicate some dependence on the nature of the chelating agent used. The biggest difference between the EDTA and DTPA experiments occurred in the solutions containing the largest concentrations of these reagents. With DTPA, chlorosis was seen only in the early stages; otherwise the plants showed normal growth. A simple chemical model for metal uptake is discussed.