Presidential address

In intact plants C¹⁴‐assimilates were translocated from the treated leaf on the primary tiller to young leaves on that tiller, to secondary tillers, and also to the roots. Plants defoliated after labelling revealed movement of materials from the storage organs to all the new leaves. Here these materials were used as a respiratory substrate and for the production of structural materials. Although initially after defoliation new leaves retained all their assimilates, presumably for their own growth, assimilates were soon translocated from these leaves to the roots.