Metal Complexation by Phytosiderophores in the Rhizosphere

Abstract

Phytosiderophores (PS) are Fe (Ill)-solubilizing compounds released from the roots of Poaceae. Although still poorly quantified, the available evidence suggests that concentrations of PS in the rhizosphere are between a few and 100 μm. Daily cycles of PS in the rhizosphere occur with inputs from plants roots in the morning, the majority of PS being degraded by microorganisms, reabsorbed by plants, or adsorbed to soil solids throughout each day. Release of PS due to Fe deficiency, and direct uptake of the Fe(III)-PS complex by grass roots have been well demonstrated, but the release of PS in response to other metal deficiencies and the uptake of other metal-PS complexes is more controversial...