Figure 8.

Unidirectional uptake of ²²Na⁺ (A–C) and ⁸⁶Rb⁺ (D) into leaf blades and sheaths after 2 h root exposure to radioactively labeled solution (all solutions contained 25 mm NaCl and 2 mm CaCl₂ in half-strength modified Hoagland with K⁺ replaced with Rb⁺ in D). Uptake is expressed as the concentration of Na⁺ or Rb⁺ per leaf organ (nmol g FW⁻¹) and as the ratio of sheath to total leaf uptake (measured as nanomole content). A to C, Uptake of Na⁺ into salt tolerant line 149 (A and C) and salt sensitive Tamaroi (B and C). D, Uptake of Rb⁺ into roots, total shoot, and sheath and blade of leaf 1, and ratio of sheath to total leaf Rb⁺ in leaf 1. Data represent mean ± sem (n = 5 [A–C]; n = 6 [D]).