Inhibition of tumor induction by auxin in totally debudded Nicotiana glauca x N. langsdorffii.

Spontaneous formation of tumors in Nicotiana hybrids, such as N. glauca X N. langsdorffii, has been shown to be under genetic control (4) and not attributable to any external causative agent. However, the mechanism by which the tumor inducing genome brings about the transformation from normal to tumorous cell growth is not understood. Recently it was postulated that the first step in tumorigenesis is the transition to meristematic activity in cells within certain potential growth centers when they are liberated from the dominance of the apical meristem (Ames and Smith, in preparation). That is to say, the trigger for tumor induction is thought to be a reduction in the level of auxin within the plant. This report describes our initial attempt to test this hypothesis.