Experiments on the Transport of Auxin

The purpose of the work described in this paper was to measure quantitatively the transport of auxin, using a new experimental technique. The original method of measuring the rate of auxin transport required the determination of the amount transported through the tissue to an agar block during a series of time intervals, thus determining the time at which the first auxin arrived (6). Since with the photokymograph (4) the beginning of the curvature can be accurately determined, and since this initial curvature occurs a known time interval after application of auxin to the recording plant, it is possible to determine for each coleoptile when auxin reaches its cut surface. Thus by placing a piece of tissue one-sidedly on a recording plant, and applying auxin to the other end of this tissue, the rate of auxin movement through it can be determined