THE NORMALIZING FACTOR FOR THE TOMATO MUTANT CHLORONERVA .39. EFFECT OF NICOTIANAMINE ON IRON UPTAKE AND CITRATE ACCUMULATION IN 2 GENOTYPES OF TOMATO, LYCOPERSICON-ESCULENTUM MILL

The nicotianamine-less tomato mutant chloronerva accumulated large amounts of iron and citrate in different organs under normal iron supply of 10-mu-M FeEDTA in the nutrient solution. A similar accumulation of citrate was obtained by the wild-type <<Bonner Beste>> only under iron deficiency and correspondingly low iron concentrations in the same organs. Application of nicotianamine (NA) to the leaves of the mutant led to a decrease both of iron and citrate concentrations down to the levels of the wild-type. The results are discussed in terms of a possible activation of iron by NA, resulting in the regulation of iron-dependent processes at the level of gene expression or of iron-requiring enzymes involved in citrate metabolism.