Phytotoxicity of high levels of iron chelates on bean plants in nutrient solution

Abstract

Bush bean plants (Phaseolus vulgaris L. cv. Improved Tendergreen) were grown for 14 days in a glasshouse in 3700 ml nutrient solutions containing 5 × 10^‐4, 10^‐3, 4 × 10^‐3 and 10^‐2 M Fe as EDDHA, EDTA, or DTPA plus a control with 5 × 10^‐5 M FeEDDHA. The solutions otherwise were complete. The FeEDTA showed phytotoxicity at 5 × 10^‐4 M, while FeEDDHA and FeDTPA showed phytotoxicity at 4 x 10^‐3 M Plants with FeEDTA were dead at 10^‐3M. Plants with 10^‐2 M FeEDDHA were not dead but were stunted and leaves were red because of the amount of FeEDDHA present in the leaves. Iron was available from the chelate sources and there were small effects only of the Fe chelates on Mn, Cu and Zn concentrations in leaves.