Kinetin-promoted transport of assimilates in stems of Phaseolus vulgaris L. : Localized versus remote site(s) of action.

Kinetin, applied as a dispersion in aqueous lanolin to the stumps of decapitated stems of P. vulgaris plants with their roots removed, was found to promote the transport of (14)C- and (32)P-labelled assimilates to the site of hormone application. Measurement of photosynthetic rate of, and assimilate export rate from the source leaves, indicated that kinetin was not acting to promote assimilate transport by stimulating these processes. Moreover, it was found that the time between kinetin application and detection of an enhanced transport flux was independent of the distance over which kinetin would need to move to be present throughout the length of the transport pathway. These observations, together with the finding that lateral applications of kinetin to the stems resulted in an enhanced localized accumulation of assimilates, provided evidence that kinetin acted locally at its point of application to stimulate assimilate transfer.