Iron: Nutritious, Noxious, and Not Readily Available

Effect of excess iron and copper on physiology of aquatic plant Spirodela polyrrhiza (L.) Schleid

“…Though iron and copper are essential trace elements for plants, being involved in many processes of metabolisms (Brown, 1978;Geider and Laroche, 1994;Marschner and Romheld, 1994), excess concentration can result in toxicity, especially in altering chromatin structure, synthesis of chlorophyll and protein, enzyme activity, photosynthesis and respiration, water content and plant biomass yield (Guerinot and Yi, 1994;Mori, 1999;Olaleye et al, 2001;Connolly and Guerinot, 2002;Burzynski and Klobus, 2004).…”

Review on iron availability in soil: interaction of Fe minerals, plants, and microbes

“…In fact, plants can affect microbes (abundance, diversity, and activity), Fe availability, and the interactions between Fe minerals and microbes as a consequence of root activity (exudation and nutrient uptake) to satisfy their need of this essential micronutrient. Therefore, the low supply of Fe III to the soil solution and the high demand of plants and microorganisms (for their intense growth) could induce a considerable level of competition for Fe in the rhizosphere (Loper and Buyer 1991;Guerinot and Yi 1994). The principal means by which soil microbes acquire Fe in Fe deficiency relies on the synthesis and release of lowmolecular-weight Fe-binding molecules called siderophores (Fig.…”

Redox enzymes in the plant plasma membrane and their possible roles

“…Buckhout et al (1989) localized the NAD(P)H-Fe 3+ -citrate oxidoreductase activity on the PM in roots of iron-starved tomatoes, plants with the 'Strategy-I' mechanism of iron acquisition (Guerinot & Yi 1994). Later it was shown that the NADPH-dependent Fe 3+ -citrate reduction was not significantly different in PM vesicles isolated from iron-deficient and iron-sufficient plants and proceeded at substantially lower rates than the NADHdependent reduction.…”

“…Plants have two general strategies for taking up iron by the roots (Römheld 1987;Guerinot & Yi 1994;Mori 1999). In Strategy-II used by graminaceous monocotyledons, Fe 3+ -chelating compounds, phytosiderophores, are synthesized in and released from the roots, Fe 3+ is complexed by the phytosiderophores, and the complexed Fe 3+ is taken up by the roots via an unidentified transport system.…”