Figure 2.

Increasing unidirectional influx of Na⁺ (in micromoles per gram per minute) into excised roots of Arabidopsis with increasing concentrations of external Na⁺ and a constant Ca²⁺ activity of 0.2 mm, fitted with a line y = 0.023x + 0.15, r² = 0.97. Data represent means, and error bars the se (n = 4).