Dissolution of iron from soils by mugineic acid

Abstract

Mugineic acid (MA; (2S, 2′S, 3′S, 3″S)-N-[3-carboxy-3-(3-carboxy-3-hydroxypropylamino)-2-hydroxypropyl]-azetidine-2-carboxylic acid), a multidentate complexing agent, is exuded by the roots of graminaceous plants (e.g. barley) growing in Fe-deficient conditions. In experiments designed to compare between the amounts of Fe dissolved by MA (FeMA), NH4-oxalate (Feo), and diethylenetriaminepentaacetic acid (DTPA) Soil Test (FeDTPA) from 38 soil samples, FeMA correlated well with FeDTPA especially for neutral to alkaline soils (pH > 6.5, r = 0.938***). The mechanisms of interaction of MA and DTPA with iron oxides appear to be similar and this probably accounts for the success of the DTPA Soil Test in predicting Fe-deficiency in graminaceous plants in neutral and alkaline soils.