Nicotianamine Concentrations in Iron Sufficient and Iron Deficient Sunflower and Barley Roots

Abstract

Summary The ferrous ion complexing compound nicotianamine (NA), widespread in the plant kingdom, has a close similarity in its chemical structure to phytosiderophores (PS). The NA concentration in Fe-sufficient sunflower root tips is 3-fold that of the basal root parts. In Fe-deficient root tips this high concentration dropped down to the basal root part level. Thus, the NA concentration seems not to be part of strategy I of the iron acquisition ability. Contrarily, in Fe-sufficient barley roots no increased NA concentration could be found in any root part, but under Fe-deficiency, if PS are synthesized, the NA concentration increased in lateral roots 5- to 6-fold. This accumulation qualifiesNA as an intermediate in the PS biosynthetic pathway and contradicts the findings of Shojima et al. (1989),whereby NA accumulation was only found in a cell-free system but not in intact roots.