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

Summary Short-term (10 min) K⁺ (⁸⁶Rb) influxes (ϕK _oc ⁺ ), rates of net K⁺ uptake (ϕK _net ⁺ ) 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 trais. ϕK _oc ⁺ 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 V_max and K_m for ϕK _oc ⁺ , of selected lines and the rates of change of these constants with root K⁺ concentration (K⁺]) showed that ϕK _oc ⁺ in AN 51 was consistently higher than in CS 40 and SH 319. ϕK _net ⁺ was also generally higher in AN 51. ϕK _net ⁺ (at different growth stages), unlike ϕK _oc ⁺ , failed to correlate with root K⁺]; ϕK _net ⁺ 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.