A SENSITIVE METHOD FOR THE DETECTION OF TRITIUM-MARKED /Cap Beta/- INDOLYLACETIC ACID IN PLANT CELLS AND TISSUES AT PHYSIOLOGICAL AND EXPERIMENTAL CONCENTRATIONS

The localization of beta -indolylacetic acid (AIA), a growth auxin, was attempted using C/sup 14/ and tritium as tracers. The radioauto histographic detection method depends on the insolubilization of AIA in situ by picric acid and basic lead acetate at a suitable pH, the AIA being protected from histological solvents. The results of the detections corresponding to physiological responses during growth tests on Pisum, Avena, Phaseolus, and Vicia, at concentrations of 10/sup -5/ and higher make possible the localization of tissues in agreement with the auxinic activity and with the relations already known between AIA and cellular formations. By increasing the time of exposures of the sections, it will be possible to attain concentrations which are much lower and more clearly physiological. (auth)