Potassium uptake efficiency of potato and wheat in relation to growth in flowing solution culture

Uptake efficiency (in terms of shoot K content) of potato decreased with ti me compared to that of wheat at a deficient K level of 1.5 muM. This result ed from the decrease in root-shoot ratio with time for potato only. Both sh oot and root growth rates of potato depended on solution K levels in the in itial stages and were greater at higher IC levels. At optimum K, uptake eff iciency of potato increased with time and this was due to the increased K-i nflux with time. The K concentration of 4-5% in the potato shoot was suffic ient to achieve 90% of maximum shoot growth rate. Plants grown at optimum K concentration attained shoot K content of 4-5% rapidly and achieved maximu m shoot growth rate faster than those grown at low K concentration.