Influence of a Crown-Gall Tumor Initiation Enhancer on Adventitious Rooting

Abstract

Summary Present work demonstrates the interference of a tumor initiation enhancer present in extract fractions derived from highly susceptible plants and closely related to their competence for tumor formation, in adventitious rooting in cuttings and in intact mung bean plants. In intact plants the tumor initiation enhancer stimulates strongly the initiation of adventitious roots, but shows a much weaker effect on the growth of these initials. On the contrary, in cuttings this active compound(s) does not greatly influence the mean number of adventitious roots. A increase is only obtained if the active compound(s) is applied after an IBA treatment. One can conclude that the tumor initiation enhancer might have a function in triggering the cells opposite to the xylem poles, resulting in the initiation of the roots, but other factors (probably auxin) are involved in regulating the division and growth of the cells concerned. Similar mechanisms could be supposed for the regulation of the tumor initiation in dicotyledonous plants.