The Dynamics of Phosphorus Uptake and Remobilization during the Grain Development Period in Durum Wheat Plants

The Dynamics of Phosphorus Uptake and Remobilization during the Grain Development Period in Durum Wheat Plants

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Post-anthesis phosphorus (P) uptake and the remobilization of the previously acquired P are the principal sources of grain P nutrition in wheat.However, how the acquired P reaches the grains and its partitioning at the whole plant level remain poorly understood.Here, the temporal dynamics of the newly acquired P in durum wheat organs and its allocation to grain were examined using pulse-chase 32P-labeling experiments at 5 and 14 days after anthesis.

Durum wheat plants were grown hydroponically under high and low P supplies.Each labeling experiment lasted for 24 h.Plants were harvested 24, 48, and 96 h dea eyewear after labeling.

Low and high P treatments significantly affected the allocation of the newly acquired P at the whole plant level.Three days (96 h) after the first 32P-labeling, 8% and 4% of the newly acquired P from exogenous solution were allocated to grains, 73% and 55% to the remainder aboveground organs, and 19% and 41% to the roots at low and high P supplies, respectively.Three days after the second labeling, the corresponding values were 48% and 20% in grains, 44% and 53% in the remainder aboveground organs, and 8% and 27% in roots at low and high P supplies, respectively.

These results reveal that the dynamics of P allocation to grain was faster in plants grown under low P supply than under high supply.However, the obtained results also indicate that the origin of P accumulated in durum wheat grains was mainly from P remobilization with 5th marine division patch little contribution from post-anthesis P uptake.The present study emphasizes the role of vegetative organs as temporary storage of P taken up during the grain filling period before its final allocation to grains.