tailieunhanh - Handbook of Plant Nutrition - chapter 11

11 Iron Julius von Sachs, the founder of modern water culture experiments, included iron in his first nutrient cultures in 1860, and Eusèbe Gris, in 1844, showed that iron was essential for curing chlorosis in vines. | 7 1 2006 7 15 AM Page 329 11 Iron Volker Römheld University of Hohenheim Stuttgart Germany Miroslav Nikolic University of Belgrade Belgrade Serbia CONTENTS Historical Determination of Functions in Plants .330 Forms and Sources of Iron in Diagnosis of Iron Status in Iron Iron Iron Concentration in Plant Part and Growth Iron Requirement of Some Iron Levels in Iron Movement of Iron within Factors Affecting Plant Soil Plant Factors .343 Soil Testing for Iron .344 Fertilizers for HISTORICAL INFORMATION Determination of Essentiality Julius von Sachs the founder of modern water culture experiments included iron in his first nutrient cultures in 1860 and Eusebe Gris in 1844 showed that iron was essential for curing chlorosis in vines 1 2 . Sachs had already shown that iron can be taken up by leaves and within a few years L. Rissmuller had demonstrated that foliar iron is obviously translocated by phloem out of leaves before leaf fall in European beech Fagus sylvatica L. . The early developments in the study of iron in plant nutrition were summarized by Molisch in 1892 3 . It was another 100 years before the principal processes of the mobilization of iron in the rhizosphere started to be understood 4-8 . 329 7 1 2006 7 15 AM Page 330 330 Handbook of Plant Nutrition FUNCTIONS IN PLANTS The ability of iron to undergo a valence change is important in its functions Fe2 1 Fe3 electron It is also the case that iron easily forms complexes with various ligands and by this modulates its redox potential. Iron is a component of two major groups of proteins. These are the heme proteins and the Fe-S proteins. In these .