Mechanism of iron uptake by plants

Summary

Brown's 1978 review synthesises the physiological basis of iron acquisition in plants, explaining how Fe-efficient species overcome bioavailability constraints in alkaline soils through root acidification and redox chemistry. The mechanism involves hydrogen ion and reductant release by roots, reduction of Fe³⁺ to Fe²⁺ at the root surface, uptake via young lateral roots, and subsequent oxidation and chelation for xylem transport to the shoot. The paper links root iron uptake efficiency to downstream plant processes including nitrogen metabolism and metal tolerance.

Regional applicability

This foundational mechanistic work is geographically agnostic and directly applicable to United Kingdom farming and horticulture, particularly on the chalk and limestone soils common in southern England where Fe chlorosis is a known constraint in fruit and vegetable production. Understanding Fe-efficiency mechanisms remains relevant to UK soil and crop management.

Key measures

Iron uptake pathways; Fe-efficiency classification; pH at root zone; reduction of ferric to ferrous iron; Fe2+ translocation through protoxylem and metaxylem; chelation by citrate; nitrate reductase activity; heavy metal tolerance

Outcomes reported

The study describes the physiological and biochemical mechanisms by which plants take up iron from soil, particularly under Fe-deficiency stress, including root acidification, reduction of Fe³⁺ to Fe²⁺, and translocation via the vascular system. It distinguishes between Fe-efficient and Fe-inefficient plant responses and discusses downstream effects on nitrate reductase activity and heavy metal tolerance.

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