Transport and Metabolism of Kinetin-8-14C in the Mesocotyl and Coleoptile of Zea mays L.

The movement and metabolism of kinetin-8-14C in the mesocotyl and coleoptile of Zea mays have been investigated. The segments (10 mm) of coleoptile with and without an apex were used. The presence of apex decreases the quantity of counts which move basipetally in the segments. The quantity transported acropetally in the segments (apex in contact with receiver blocks) was about three times higher than that transported basipetally (apex in contact with donor blocks). Using 10 mm coleoptile segments excised I mm below the apex, there was no appreciable difference between acropetal and basipetal movement. The transport of kinetin in the mesocotyl was studied with and without vascular tissue. The quantity transported in segments without vascular tissue was always lower than in the segments with vascular tissue. The presence of the node between the coleoptile and mesocotyl does not disturb the movement of kinetin in the basipetal position (node in contact with donor blocks). Thin layer chromatography of plant extracts after a 48-hour transport period revealed several radioactive substances which appeared to be adenine with Rf 0.5 and other components appeared at Rf 0.6.