Question

Organic acids mobilise P but they are also rapidly decomposed. Explain by which mechanisms plants increase the effectiveness of organic acids in mobilising P.

Answer 1

• Malate doesnot mobilises P (Phosphorus), but this has been overcomed by organic acids such as citrate, where it is further broken down only in the soil and hence mobilise P present inn Ca-P rich soil from one soil to another type. This is due to the action of protons and citrate anion released from the citric acid when in contact with the soil.
• The release of low molecular weight organic acids into the soil, especially near the rhizosphere. makes its ability to uptake more Phosphorus.
• Hence, the major mechanism involved here is the ability of organic acids to fuse with metal cations available in the soil thereby competing with the phosphorus to adsorb to the soil and hence releasing these P to other sites.