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Interactions
Among Soil Components:
Chelates
A
chelate (from Greek chele
= claw) is an organo-metal complex in which an organic molecule
combines with a metal atom by way of two or more chemical bonds.
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Chelate: Structural
formula for ferric gluconate (common iron chelate)
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Image Source:
Lesley Dampier & Centre for Teaching, Learning and Technology, UBC
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Organic molecules that chelate with metals
include:
- Substances
that are synthesized by roots
- Various
humic substances that have multiple carboxyl groups
- Synthetic
substances
Importance
of chelates
- Dispersed and dissolved
chelates readily release metal ions and contribute to nutrient
metal availability. Fulvic
acids form chelates which provide nutrients to plants.
- Undispersed (flocculated) and
undissolved or excessively stable chelates, contribute to
nutrient deficiency. Humic
acids and humins form very stable chelates.
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At Flocculate and Dispersed
Organic Molecules
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Click
on the image to review
- flocculated and dispersed organic molecules.
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Image Source: Centre for Teaching, Learning and Technology, UBC
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Siderophores
Under Fe-deficiency conditions certain
microbes and roots produce chelating ligands called siderophores.
These ligands bond with Fe3+ and maintain
relatively high concentrations of soluble iron.
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