Rice increases phosphorus uptake in strongly sorbing soils by intra-root facilitation

Area of Science:

• Agricultural Science
• Plant Physiology
• Soil Science

Background:

• Upland rice (Oryza sativa) thrives in phosphorus (P)-deficient soils, yet P uptake mechanisms remain unclear.
• Existing models often underestimate P uptake, hindering the development of improved rice ideotypes.
• Understanding P acquisition is crucial for enhancing crop yields in challenging environments.

Purpose of the Study:

• To develop and validate a novel model simulating phosphorus uptake in upland rice.
• To elucidate the root system's role in P acquisition, particularly in P-sorbing soils.
• To identify key root traits for optimizing phosphorus uptake in rice.

Main Methods:

• A new model was developed incorporating root morphology at the rhizosphere scale, including root hairs and S-type laterals.
• The model simulates fast- and slowly reacting soil P pools and root-induced pH changes.
• Model simulations were validated against experimental data of P uptake in a P-efficient rice genotype over 48 days.

Main Results:

• The novel model accurately simulates P uptake by P-efficient upland rice.
• Simulations show that the root's P solubilization zone extends beyond its depletion zone.
• S-type laterals, characterized by root hairs, are identified as key structures for maximizing P uptake by positioning them effectively within these zones.

Conclusions:

• Thicker roots support P uptake by fine lateral roots, with S-type laterals playing a critical role.
• Optimizing P uptake involves strategic placement of laterals within the root's pH modification and P solubilization zones.
• Enhanced P uptake is achievable through longer root hairs and increased root length density, rather than solely total root length.