01337naa a2200241 a 450000100080000000500110000800800410001910000170006024500550007726000090013252007530014165000090089465000140090365000120091765000180092965000100094765000150095765000110097265300200098365300210100365300100102477300610103417938331999-03-02       1984    bl ---       0--  u    #d1 aSMITH, B. N.  aIron in higher plantsbstorage and metabolic role.  c1984  aIron in the earth's crust is more oxidized now than it was when life envolved. Generrally iron is available in the soil in the ferric form but must be taken up and utilized in the ferrous form. While iron is essential for life in small amounts, higher concentrations are toxic. Plants store iron for future use as ferritin which is ferric phosphate coated with protein. The protein coat apparently prevents iron toxicity or use of stored iron by pathogens. Iron is found in both heme-proteins (cytochromes, catalase, etc.) and non-heme proteins (ferridoxins, nitrite reductase, etc.) These enzymes are characterized by involvement in oxidation-reduction reactions involving electron or proton transfer. One might say that life envolved around iron.  airon  anutrition  astorage  aArmazenamento  aFerro  aNutrição  aPlanta  aMetabolico role  aPapel metabolico  aPlant  tJournal of Plant Nutritiongv.7, n.1/5, p.759-766, 1984.