Role of chelahon by ortho dihydroxy phenols in iron absorption by plant roots

Abstract

Abstract Under conditions of iron stress, certain higher plants are able to exude ortho‐dihydroxyphenols (including caffeic acid) into the root medium. These compounds can reduce ferric iron to the more soluble ferrous form. By the use of radioactive 14C we have shown that caffeic acid (or a degradation product) can be reabsorbed by plant roots (Hordeum vulgare) and that absorption of ferrous iron can be enhanced several‐fold by the presence of the caffeic acid. The finding is attributed to the chelation of ferrous iron and movement of the chelated species into the roots. An analagous mechanism in stressed microorganisms for enhancing availability of ferric iron by means of chelation has been reported previously. Key words: Iron absorption 14C‐caffeic acidchelation