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 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 2000 dodge dakota catalytic converter 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 skin of the flayed one 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 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.