Restricted root-to-shoot translocation appears to be the key determinant of Cd accumulation in all shoot tissues (view whole-plant animation). Retention of Cd in the roots may limit Cd accumulation in grain by directly controlling Cd translocation from roots during grain filling, or by controlling the size of shoot Cd pools that can be remobilized to the grain.

Two patterns of Cd accumulation are evident in the shoots (excluding grain). The spikelets, leaves and vegetative tillers increase in Cd content during grain filling (view spikelets, leaves & tillers animation), whereas the stems show negligible change in Cd content (view stem animation).