Movement of radioactivity from [(3)H]GA 3 in geotropically stimulated coleoptiles of Zea mays.

The movement of radioactivity from [(3)H]GA3 has been studied in horizontal and vertical segments of Zea mays coleoptiles. No evidence was obtained for the polar movement of radioactivity within the segment, and no radioactivity significantly above background was detected in the receiver blocks. A gradient of radioactivity was not established between the upper and lower halves of horizontal segments supplied at their apical ends with a symmetrical donor block, and again no radioactivity was recovered in the basal receiver blocks. An enhanced lateral movement of radioactivity could not be detected in horizontal segments supplied with asymmetrical donor blocks at their apical ends.