Genetic differences among wild oat lines in potassium uptake and growth in relation to potassium supply

Short-term (10 min) K⁺ (⁸⁶Rb) influxes $\left( {\phi K_\infty ^ + } \right)$, rates of net K⁺ uptake $\left( {\phi K_\infty ^ + } \right)$ and growth in relation to K⁺ supply were studied in genetically pure lines of wild oat. The wild oat lines employed in this study showed substantial differences in these traits. $\left( {\phi K_\infty ^ + } \right)$ was higher in the AN lines (AN5 1, AN 474) than CS 40 and SH lines (SH 319, SH 430) in plants grown under both low and high K⁺ conditions. Kinetic constants Vmax and Km for $\left( {\phi K_\infty ^ + } \right)$, of selected lines and the rates of change of these constants with root K⁺ concentration ([K⁺]) showed that $\phi K_\infty ^ + $ in AN 51 was consistently higher than in CS 40 and SH 319. $\phi K_{ner}^ + $ was also generally higher in AN 51. $\phi K_{ner}^ + $ (at different growth stages), unlike $\phi K_\infty ^ + $, failed to correlate with root [K⁺]; K £ et values were low during the first two weeks despite lower root [K⁺]. CS 40 showed the highest utilization efficiency, produced the largest amount of biomass, absorbed most K⁺ and flowered earliest (by day 30). AN 51 had not produced flowers at day 42.