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Contribution of remobilization to the loading of cadmium in durum wheat grains: impact of post-anthesis nitrogen supply

Yan, Bo-Fang, Nguyen, C., Pokrovsky, O.S., Candaudap, F., Coriou, C., Bussière, S., Robert, T., Cornu, J.Y.
Plant and soil 2018 v.424 no.1-2 pp. 591-606
cadmium, cultivars, dry matter partitioning, durum wheat, filling period, flowering, hydroponics, leaves, nitrogen, stable isotopes
AIMS: This study focuses on quantifying the contribution of remobilization to the amount of cadmium accumulated in durum wheat grains. The impact of post-anthesis N supply was tested in two cultivars that differ in their shoot biomass partitioning. METHODS: Two French durum wheat cultivars were grown hydroponically and exposed to 100 nM Cd. After anthesis, the plants were fed with a solution enriched in the stable isotope ¹¹¹Cd to trace the Cd newly absorbed, and subjected or not to nitrogen deprivation. Plants were sampled at anthesis and grain maturity to assess the post-anthesis fluxes of Cd and N among organs. RESULTS: Cd remobilized from pre-anthesis stores contributed to more than half of the Cd accumulated in mature grains. Cd was mainly remobilized from stem and poorly remobilized from leaves. Stopping N supply during grain filling enhanced N remobilization but had no impact on post-anthesis uptake and remobilization of Cd, and thereby, on Cd concentration in grains. No difference was observed between the two cultivars in the contribution of Cd remobilization and its dependence toward post-anthesis N supply. CONCLUSIONS: Cd remobilization significantly contributes to the accumulation of Cd in durum wheat grains. Cd remobilization is not tightly linked with N remobilization and behaves like a senescent-independent process in durum wheat.