Polar Transport of Calcium in The Primary Root of Zea mays.

Transport of calcium-45 in 20-mm root segments is basipetal and requires metabolic maintenance. Such transport reaches a maximum rate after immersion of the roots in tracer solution for approximately 12 hours and is still pronounced after 50 hours. Acropetal movement is slight, probably non-metabolic, and essentially constant. Amounts transported are linearly dependent on the absorbing area exposed to tracer solution.