AUXIN-PROMOTED TRANSPORT OF METABOLITES IN STEMS OF PHASEOLUS-VULGARIS L - FURTHER-STUDIES ON EFFECTS REMOTE FROM THE SITE OF HORMONE APPLICATION

The proposal that indol-3yl-acetic acid (IAA) regulates acropetal transport in stems by acting along the transport channel was further investigated using decapitated seedlings of Phaseolus vulgaris. Concentrations of two inhibitors of auxin transport, which did not interfere with IAA-promoted basipetal transport, were found to decrease the IAA-promoted component of acropetal metabolite movement. This latter inhibition was relieved by treating the stems with a supplementary supply of IAA below the point of inhibitor application. These observations, together with the finding that the response time of transport to hormone action was strongly dependent on the distance over which IAA needed to move to be present throughout the length of the transport channel, provide support for the above proposed mode of IAA action. © 1979 Oxford University Press.