Which form of phosphorus is essential for plant growth?

The essential form of phosphorus for plant growth is PO4-P, or phosphate ion. This form of phosphorus is readily available for uptake by plant roots and is crucial for various physiological processes, including energy transfer (as it is a component of ATP), photosynthesis, and the synthesis of nucleic acids. Plants absorb phosphorus in its ionic form, specifically as phosphate (PO4^3-), which is involved in cellular activities that are vital for growth and development.

The other choices represent different forms of phosphorus, but they are not the primary form that plants absorb. P2O5 is a common notation used for fertilizers indicating the total phosphorus content but does not directly represent a plant-available form. H2PO4^- is another form of phosphate, but it is specifically the dihydrogen phosphate ion, which can also be absorbed by plants, but PO4-P encompasses the broader term for plant-available phosphorus. Lastly, Ca3(PO4)2, or calcium phosphate, is a solid mineral that can release phosphate in the soil, but it needs to go through a transformation to become plant-available, making PO4-P the most immediate and essential source for plants.

Understanding the specific forms of nutrients and their availability is critical for effective