Necessity of Indoleacetic Acid for the Duplication of Crown-Gall Tumor Cells.

Abstract

The reduction of the endogenous or biologically effective level of IAA in crown-gall tumor tissues was accomplished in vivo and in vitro by the use of ionizing radiations (x-rays, gamma rays, and fast neutrons) and by the use of a specific antimetabolite for IAA. In all cases, the primary effects were a reduction in the growth of the tissues. These growth inhibitions could be reversed wholly or in part by supplying the tumor tissue with appropriate concentrations of IAA. The results gave presumptive evidence that IAA may specifically be required for the duplication of crown-gall tumor tissues which presumably synthesize optimal amounts of auxin.