Iron is an essential micronutrient for almost all living organisms because it plays critical role in metabolic processes such as photosynthesis, DNA synthesis and respiration. Further, many metabolic pathways are activated by iron, and it is a prosthetic group constituent of many enzymes.
Limited iron (Fe) availability in soils is one of the main limiting factors of yield and quality of agricultural productions worldwide, particularly in alkaline and calcareous soils. This poor availability is closely linked to physical, chemical, and biological processes within the rhizosphere as a result of soil–microorganism–plant interactions.
Iron shortage in plants might be prevented by the application of Fe fertilizers either at the soil or leaf level. Fertilization of Fe has been lately also used not only to counteract limited Fe uptake but also to enhance Fe allocation obtaining Fe-enriched crops (i.e., biofortification).
Iron plays a significant role in various physiological and biochemical pathways in plants. It serves as a component of many vital enzymes such as cytochromes of the electron transport chain, and it is thus required for a wide range of biological functions. In plants, iron is involved in the synthesis of chlorophyll, and it is essential for the maintenance of chloroplast structure and function. Because of its redox properties, its long distance and intracellular trafficking require specialized proteins and low molecular mass chelates because of its insolubility and toxicity in presence of oxygen.
An imbalance between the solubility of iron in soil and the demand for iron by the plant are the primary causes of iron chlorosis. They include root hair morphogenesis, differentiation of rhizodermal cells into transfer cells, yellowing of leaves and ultrastructural disorganization of chloroplasts and mitochondria, as well as increased synthesis of organic acids and phenolics, and activation of root systems responsible for an enhanced iron uptake capacity.
 Fe deficiency impairs plant ionome at the whole, since synergisms and/or antagonisms among elements occur in the plant–soils system. An adequate availability of Fe is needed to guarantee an optimum plant performance and growth, yet the chemical form of the metal, i.e., its speciation, is also crucial and able to influence gene regulation, metabolic activity and elements distribution within cells and within plants.
On iron resupply, these changes disappear within few days and a transient accumulation of the iron storage protein ferritin in the plastids is one of the early events in this process. Iron excess can also occur in plants where it elicits an oxidative stress leading to necrotic spots in the leaves. Induction of ferritin synthesis is again an early event of the plant response to this iron toxicity. Plant hormones such as auxin, abscisic acid and ethylene, as well as reactive oxygen intermediates play an important role in the transduction pathways, allowing plants to respond to these iron-deficiency and excess stresses. Similarities and differences among the various mechanisms responsible for iron uptake plants and yeast are outlined. Relationships between iron and copper metabolism are also indicated.
To ensure Fe acquisition, two distinct physiological strategies have evolved in plants, one based on Fe(III) reduction (Strategy I) and the other on the chelation of Fe(III) (Strategy II).
All plants, with the exception of grasses, rely on the reduction-based Fe acquisition Strategy I, which involves an acidification of root apoplast and rhizosphere, mediated by P-type ATPases.
In gramineous monocots (grasses), another mechanism, called Strategy II, has evolved. This includes the synthesis and release of phytosiderophores, which are metal ligands belonging to the mugineic acid family. They are synthesized from methionine via Na (Sodium). Although both monocots and dicots produce NA, only grasses produce phytosiderophores.
Conclusion
Established in 1974, one of the most convenient source of high purity iron, Industrial Metal Powders (India) Pvt. Ltd is delivering the world’s most convenient form of iron for food fortification as well as biofortifications since long time. As the purity is more than 99.5% with min impurities, it helps to make the good quality of iron chelated and ferrous salts to make as micronutrient in fertilizers. Due to its excellent bioavailability, it gets improve the absorption of iron into different crops and support to get the essential iron to the plants.
