Regreening properties of the soil slow-mobile H₂bpcd/Fe³⁺ complex: Steps forward to the development of a new...

The application of synthetic Fe-chelates stands for the most established agronomical practice to alleviate lime-induced chlorosis, which still constitutes a major agronomic problem. However, the percolation through the soil profile due to the negative charge of the most deployed molecules results in agronomical and environmental problems. H₂bpcd/Fe³⁺ complex features distinctive chemical characteristics, including moderate stability of the Fe(bpcd)⁺ species (logβ = 20.86) and a total positive charge, and we studied its behavior in soil and regreening effects on cucumber plants. Soil column experiments have underlined that H₂bpcd/Fe³⁺ is retained in more amounts than EDDHA/Fe³⁺. The new ligand was not proven to be toxic for the cucumber and maize seedlings. A concentration of 20 μM H₂bpcd/Fe³⁺ attained regreening of Fe-deficient cucumber plants grown in the hydroponic solution supplied with CaCO_3, similar to that shown by EDDHA/Fe³⁺. Experiments with a 2 μM concentration of ⁵⁷Fe showed that cucumber roots absorbed H₂bpcd/⁵⁷Fe³⁺ at a slower rate than EDTA/⁵⁷Fe³⁺. The high kinetic inertness of H₂bpcd/Fe³⁺ may explain such behavior.