Variations among rice cultivars in subcellular distribution of Cd: The relationship between translocation and grain accumulation

•Rice cultivars differed largely in Cd translocations from shoots to grains.•Grain Cd levels correlated with Cd translocation factors from shoots to grains.•Rice cultivars differed in Cd distributions in cell wall and soluble fractions.•Cell wall plays a main role in Cd deposition in rice shoot.•Soluble fraction is the main Cd pool in rice shoot for transport into the grain.