Phosphorus uptake, partitioning and redistribution during grain filling in rice

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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.

Proposed model of upward P fluxes in rice plants before (A) and after (B) flowering.
Proposed model of upward P fluxes in rice plants before (A) and after (B) flowering. Model variations B1 and B2 represent the two possible reproductive fluxes enabling P to be loaded into grains, that is either using roots (B1) or vegetative tissues (B2) as the main secondary P source. Size of arrows is proportional to the amount of P mobilized by fluxes from sowing to flowering (A) and during grain filling (B) measured in Opt-P treatment of the hydroponic study. Values in italic depict the percentage of 33P activity in plants 24 h after spiking in Opt-P.

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.

Reference

Cécile Julia, Matthias Wissuwa, Tobias Kretzschmar, Kwanho Jeong, Terry Rose, 2016, 'Phosphorus uptake, partitioning and redistribution during grain filling in rice', Annals of Botany, vol. 118, no. 6, pp. 1151-1162 http://dx.doi.org/10.1093/aob/mcw164


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