Synthesis and characterization of the Schiff base Fe(II) complex as a new iron source in nutrient solution

Abstract

Supplying available iron (Fe) for plant growth in hydroponic nutrient solutions is a great challenge. The chelators commonly used to supply Fe in nutrient solutions have several disadvantages such as the production of photodegradable compounds and may negatively affect plant growth by toxic side effects on plants and impaired micronutrient balance. PurposeIn this study, a new complex of Fe(II)-triethylenetetramine di salicylaldehyde (Fe-TETDSA) was synthesized and applied to a nutrient solution. MethodsFe-TETDSA was synthesized by the traditional Schiff base prepration method and characterized by FT-IR, Raman, UV–Vis, photoluminescence, molar conductivity and elemental analysis. Fe-TETDSA (with single and double dose) was evaluated as a new Fe source for corns grown in nutrient solution compared to the Fe-EDTA and Fe-EDDHA, as well as FeSO4. ResultsThe Fe-TETDSA was stable in alkaline pH. Application of Fe-TETDSA chelate significantly increased root and shoot dry weight corns compared to Fe-EDTA and Fe-EDDHA. The total Fe concentration of plants supplied with Fe-TETDSA was more than those supplied with Fe-TETDSA2 and Fe-EDDHA. . Corn plants treated with Fe-TETDSA chelates also accumulated significantly higher levels of Zn (zinc) and N (nitrogen) in their shoots compared with those treated with Fe-EDTA and Fe-EDDHA. But the application of Fe-TETDSA (single and double dose) decreased Cu and Mn concentration in corns shoot. Application of Fe-TETDSA, Fe-TETDSA2 and Fe-EDDHA showed the highest SPAD index in corns leaves. ConclusionsThe results showed that Fe-TETDSA may be a sustainable alternative to traditional synthetic chelating agents such as EDTA or EDDHA in nutrient solution.