Effect of nicotianamine on iron uptake by the tomato mutant ‘chloronerva’

Abstract

In the tomato ( Lycopersicon esculentum L.) mutant ‘chloronerva’ the biosynthesis of nicotianamine, a derivative of the amino acid azetidine‐2‐carboxylic acid, is blocked. Application of nicotianamine to leaves of seedlings of the mutant reduced the abnormally high iron content of the plants to the level of the wild‐type. In short‐term experiments nicotianamine decreased the amount of iron removed from the nutrient medium by isolated roots of both wild‐type and mutant. Addition of nicotianamine to the nutrient solution at 10 −5 M inhibited the excessive iron uptake by the mutant and wild‐type. This effect was more evident with 59 Fe‐ethylenediamine‐N, N′‐bis‐( o ‐hydroxyphenylacetic acid) than with 59 FeCl 3 as the iron source. It is concluded that nicotianamine plays a direct or indirect role as a regulator of iron uptake in plants.