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Mechanism of iron uptake by plants
Author(s) -
BROWN JOHN C.
Publication year - 1978
Publication title -
plant, cell and environment
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.646
H-Index - 200
eISSN - 1365-3040
pISSN - 0140-7791
DOI - 10.1111/j.1365-3040.1978.tb02037.x
Subject(s) - ferrous , chemistry , chelation , phosphate , soil water , nitrate , inorganic chemistry , biochemistry , biology , ecology , organic chemistry
. Green plants require a continuous supply of Fe as they grow, because Fe does not not move from the older to the newer leaves. Soils do not lack Fe per se , but it may not be available to plants grown in alkaline soils. Plants are classed ‘Fe‐efficient’ if they respond to Fe‐deficiency stress by inducing biochemical reactions that make Fe available in a useful form, and ‘Fe‐inefficienT’ if they do not. Iron uptake induced in response to Fe stress involves release of hydrogen ions and reductants by the root. The lowered pH and presence of reductant at the root zone, along with reduction of Fe 3+ to Fe 2+ at the root surface, enables Fe 2+ to be taken up primarily through the young lateral roots. Ferrous iron is present throughout the protozylem and may or may not have entered the root by a carrier. The root‐absorbed Fe 2+ is oxidized to Fe 3+ at the junction of the protoxylem and the metaxylem, chelated by citrate, and then transported in the metaxylem to the plant top. In the plant, the chemical reactions injuced by Fe‐deficiency stress may affect nitrate reductase activity, use of Fe from Fe 3+ phosphate and chelating agents, and tolerance to heavy metals. An efficient mechanism for Fe uptake in roots appears to be important for the efficient use of Fe in plant tops.