Figure 6.

K⁺ accumulation in guard cells of Adiantum epidermis. Epidermal fragments prepared from the dark-adapted leaves were kept in the dark for 1 h in 5 mm MES, 50 mm KCl, and 0.1 mm CaCl₂, pH 6.5. The fragments were then irradiated by red light at 30 μmol m⁻² s⁻¹ for 2 h in the same solution. K⁺ was stained with sodium hexanitrocobaltate (III). A, Kept in darkness; B, irradiated by red light; C, irradiated by red light in the presence of 20 μm DCMU. Scale bar in A = 30 μm.