Phosphorus (P) use efficiency in rice is linked to tissue-specific biomass and P allocation patterns

Phosphorus (P) is a non-renewable resource which may be depleted within next few decades; hence high P use efficiency is need of time. Plants have evolved an array of adaptive mechanisms to enhance external P acquisition and reprioritize internal utilization under P deficiency. Tissue specific biomass and P allocation patterns may affect the P use efficiency in plants. six rice cultivars were grown in solution culture for 20 days and then were divided into two groups to receive either adequate P or no P that were harvested at 30, 40 and 50 days. Plants were dissected into various tissues/organs. Two rice cultivars viz Super Basmati (P-inefficient) and PS-2 (P-efficient) were grown in soil with no or 50 mg P kg^-1 soil till maturity. Rice cultivars PS-2 and Basmati-2000 had higher P uptake, utilization efficiency and internal remobilization than other tested cultivars after P omission. Young leaves and roots were the major sinks while stems and mature leaves were the sources of P during P omission. In conclusion, biomass allocation and P accumulation among various tissues and P remobilization were major factors responsible for P efficiency.