Functions of Fe :- Visual symptoms :- Predisposing factors:- Corrective measures :- In soils, iron is predominantly found as chelates of ferric form (Fe+3) and it has to be reduced to ferrous form (Fe+2) on the root surface before it is taken into cytoplasm. Iron is a constituent of cytochromes, catalases, peroxidases and ferridoxin, which act as electron transmitters in basic metabolic processes. Iron deficiency results in the decline of catalase and peroxidase activity. Lower peroxidase activity impairs lignification and hence phenolics accumulate in the rhizodermis. In leaves 80% of iron is present in chloroplasts as phytoferritin. Positive correlation between total iron content of the leaves and the chlorophyll content was recorded when iron is sub optimal in nutrient solution. Inhibition of root elongation, increase in the diameter of the apical root zone, abundant root hair formation, formation of rhizodermal transfer cells (for iron uptake) are some of the changes associated with iron deficiency. Iron deficiency results in interveinal chlorosis of the younger leaves. Fine reticulate pattern is observed in newly formed leaves. The darker green veins contrasting markedly against lighter green or yellow background is observed. Iron deficiency occurs when Fe is not in available form. High carbonates in calcareous soils, high Ca in soil solution, high pH level are some of the causes for Fe deficiency. Copper toxicity induced iron chlorosis is a common occurrence in the light soil tobacco nurseries. Iron deficiency in the nurseries can be corrected by foliar application of ferrous sulfate and in the field crop through soil application of chelated iron compounds.

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