A comparative study on the efficacy of synthetic organic ligands on functional iron status in plants

Abstract

Improving functional Fe status through the application of Fe with synthetic organic ligands is a strategy to overcome the Fe-deficiency problem. The study emphasizes on the potential efficiency of different selected synthetic organic ligands (Fe-EDTA, Fe-EDDHA, Fe-Citrate) and compare their effectiveness in improving functional Fe status by biochemical means and how wheat responds to different Fe ligands at a lower supply of Fe supply, 25 µM (c.f. 150 µM in maize) under hydroponics. Wheat (Triticum aestivum) and maize (Zea mays) plants grown under a hydroponic system. Fe was supplied as either FeCl3 or in complex with organic ligands, viz., EDTA, EDDHA, and citrate. Wheat plants exhibited improved functional Fe status, as indicated by high chlorophyll and carotenoids concentrations, lipid peroxidation, and ferric chelate reductase activity in Fe-EDTA and Fe-Citrate-supplied plants. Interveinal chlorosis along with mildly increased superoxide dismutase activity was observed in FeCl3, and Fe-EDDHA-supplied plants. Chlorotic leaves of Fe-EDDHA show a decrease in lipid peroxidation, highlighting the role of Fe in chlorophyll biosynthesis and lipid peroxidation in wheat plants. Fe-EDDHA was found to be an inefficient Fe supplier for wheat too, as indicated by decreased growth with a low shoot Fe concentration (c.f. maize at 150 µM supply). Both maize and wheat are strategy II plants, but wheat is more efficient than maize plants. Fe-EDTA and Fe-Citrate have been proven to be effective Fe-suppliers in comparison to Fe-EDDHA and FeCl3 in wheat plants. Fe-EDDHA is a poor Fe supplier in hydroponic systems as EDDHA forms a strong complex with Fe and its aromatic and hydrophobic nature.