Figure 3.

Effect of growth on CaSO₄ solution and subsequent provision and withdrawal of K⁺ on HKT1 mRNA expression in roots of the barley cv Jackson. Plants were grown on K⁺-free CaSO₄ solution for 4 d (lane 1) or 5 d (lane 2). Plants were then exposed to 1.25 mm K⁺ for 1 d, which suppressed HKT1 mRNA levels. K⁺ was then withdrawn for 0 h (lane 3), 1 h (lane 4), 2 h (lane 5), 4 h (lane 6), 6 h (lane 7), 8 h (lane 8), 12 h (lane 9), and 24 h (lane 10). Fifteen micrograms of total RNA was loaded into each lane. Probing was as in Figure 2.