Phosphorus (P) found in rice grains originates from two possible sources that are exogenous (post-flowering P uptake from soil) or endogenous (P remobilisation from vegetative parts). Julia et al. investigate P partitioning and P remobilisation throughout rice grain filling.
They demonstrate that post-flowering P uptake from soil is a critical contributor to the grains’ P content in irrigated rice. In the light of a P tracer study, and propose a model of P loading into grains that should be considered in any attempt to breed rice cultivars with lower grains P content.