Abstract: | The polarity of radioactive IAA transport in segments of theleaf sheath base of Avena fatua L. is reversed upon their inversionthrough 180° transport towards the apex being greater thantowards the base. Changes in rates of transport leading to thisreversal can be detected within 1020 min, correlatingwith the timing of statolith movements from the base to theapex of statocyte cells and conforming to a proposed model forthe gravity control of auxin transport. Transport of H3-trytophan-derived H3-IAA was found to undergosimilar changes in polarity upon re-orientation as did exogenouslyapplied H3 or C14 IAA. It is concluded that the proposed modelalso relates to the movement of endogenously produced IAA. |