Chelation and Mineral Nutrition

CHELATION is a natural process. In order to prevent absorbed nutrients from precipitation resulting from the interaction of nutrients, such as iron forming precipitation with phosphorus, upon entering plant cells cationic nutrients will immediately form chelates with ORGANIC ACIDS such as citric acids, malonic cid, and some amino acids. This chelation process will then enable the nutrients to move freely inside the plants.

CHELATION in soil increases nutrient availability to plants. Organic substances in the soil either applied or produced by plants or microorganisms are the natural chelating agents. The most important substances having this nature are Hydroxamate Siderophores, Organic Acids and Amino Acids.
Hydroxamate Siderophores are naturally produced by soil microorganisms and are essential in natural ecosystems to solubilize and transport nutrients, especially iron to plant roots. Under Iron deficient I conditions, microorganisms will produce siderophores to overcome the iron starvation. Neilands and co-workers at the University of California found that Rhizobium meloti was able to correct the iron starvation using this mechanism. Neilands, Cline and co-workers of Colorado State University reported the abilities and mechanisms by which sunflower and sorghum acquire iron supplied as a ferrated hydroxamate siderophore. Research on oats by Read and co-workers of Colorado State and the University of Texas found that the absorption of iron from ferrichrome was nearly two orders of magnitude greater than that from the EDDHA treatment when there was excess supply of the ligand. Their results indicated that iron uptake by monocots may be more efficient from naturally occurring chelates than from synthetic chelates.
Organic acids and amino acids such as citric acid and glycine are also naturally occurring chelating agents. Glycine is the simplest amino acid with a molecular weight of 75. Chelates of glycine with cations such as iron, zinc, and copper have been fully studied