Phosphate-solubilising microorganisms mainly increase plant phosphate uptake by effects of pH on root physiology

Organisms intended to solubilise soil phosphate are chosen on their ability to produce a clear halo on a plate containing a sparingly soluble phosphate. This involves production of acidity. However, if these organisms establish on plant roots any benefit from increased acidity is likely to be as a result of increased rate of uptake of phosphate by plant roots rather than from increased desorption of phosphate from soil.