Correlation between inactivation of 2,4-dichlorophenoxyacetic acid & cessation of callus growth in bean stem sections.

In a previous publication (1) we have described an in vitro system for studying the callus growth on bean stem sections which is initiated by applying relatively high concentrations of 2,4-dichlorophenoxyacetic acid (2,4-D). Only short exposure to 2,4-D was necessary to initiate the callus growth. Since this growth is not tumorous in nature and therefore not auxin autonomous, it will continue only as long as there is a supply of the growth inducing material still present in the tissue. It was of interest, therefore, to follow the fate of C14-labeled 2,4-D in this system and to attempt to correlate it with the data on callus growth. This paper will report the results of these experiments.