Resumen:
Previous studies have shown that natural heteromolecularcomplexesmight be an alternative to synthetic chelates to correct iron (Fe)deficiency. To investigate the mechanism of action of these complexes,we have studied their interaction with Ca2+ at alkalinepH, Fe-binding stability, Fe-root uptake in cucumber, and chemicalstructure using molecular modeling. The results show that a heteromolecularFe complex including citric acid and lignosulfonate as binding ligands(Ls-Cit) forms a supramolecular system in solution with iron citrateinteracting with the hydrophobic inner core of the lignosulfonatesystem. These structural features are associated with high stabilityagainst Ca2+ at basic pH. Likewise, unlike Fe-EDDHA, rootFe uptake from Ls-Cit implies the activation of the main root responsesunder Fe deficiency at the transcriptional level but not at the post-transcriptionallevel. These results are consistent with the involvement of some plantresponses to Fe deficiency in the plant assimilation of complexedFe in Ls-Cit under field conditions.
