Variability in grain cadmium concentration among durum wheat cultivars: impact of aboveground biomass partitioning

Aims Varietal screening was conducted to characterize how French durum wheat lines (Triticum turgidum L. subsp. durum) differ in the concentration of cadmium (Cd) in their grains and to identify the main (eco) physiological processes behind these differences. Methods Eight French and two Canadian durum wheat lines were grown hydroponically in a nutrient solution with a low concentration of Cd (2 nM). At maturity, the partitioning of biomass and Cd among organs was analyzed and elemental profiles of the grain were obtained. Results Grain Cd concentration ranged from 0.03 to 0.08 mu g g(-1) and was thus in the same range as that measured in field trials. The level of Cd in the grain was correlated with levels of P, Mn and Zn. French lines behaved like high-Cd cultivars. A 2.4-fold variation in grain Cd was observed within French lines, which was not explained either by a difference in uptake or by a difference in the root sequestration of Cd. One important finding is that the leaf biomass was the most influential variable explaining the genotypic variation in grain Cd observed within French lines. Conclusions The partitioning of aboveground biomass may influence the concentration of Cd in grain, in addition to the sequestration of Cd in roots.