Wounding Response in Relation to Polar Transport of Radiocalcium in Isolated Root Segments of Zea mays

Abstract

A perfusion bridge technique is described which permits the simultaneous collection of exudations from both ends of corn root segments. By exposing the central portion of the segments to radio-calcium, the amounts and rates of tracer movement in either direction may be determined. A peak in both acropetal and basipetal transport rate occurs at approximately 90 min. after exposure to tracer, followed by an acropetal transport decline to zero and a basipetal transport increase, after a similar decline to relatively low rates, to a constant steady-state value. After polar transport is achieved, a fresh apical cut causes the resumption of acropetal transport. A possible explanation of this complex transport behavior is advanced.