Root-mediated ferric reduction-responses to iron deficiency, exogenously induced changes in hormonal balance and inhibition of protein synthesis

The effects of the auxin analogue 2,4-dichlorophenoxyacetic acid (2,4-D), the translation inhibitor cycloheximide (CHM) and iron deficiency on electron transport activities in roots have been investigated. Deprivation of an external Fe supply caused an increase in capacity to reduce both FeEDTA and the artificial electron acceptor ferricyanide. With respect to the iron stress-induced redox activity, bean (Phaseolus vulgaris L.) roots reduced both substrates at equal rates, while roots of Plantago/anceolata L. exhibited clearly higher rates with FeEDTA. The iron stress-induced FeEDTA and ferricyanide reduction activities were unequally affected by CHM in both species, reflecting the differences in substrate specificity.