Figure 6.

Analysis of relative intracellular K⁺ content shows that depression of K⁺_in channel activity reduces K⁺ uptake in guard cells of transgenic K⁺_in channel depressor line numbers 15-4 and 22-6 during light-induced stomatal opening. Examples of SHC-stained Arabidopsis stomatal complexes from wild-type Arabidopsis before (A) and after (B) light incubation for 30 min. Examples of SHC-stained stomatal complexes from transgenic K⁺_in channel depressor line number 22-6 before (C) and after (D) light incubation for 30 min. E, Relative intracellular K⁺ content in guard cells of wild type, vector-transformed control, and transgenic K⁺_in channel depressor line numbers 15-4, 22-6, and 23-4. Black bar and white bar represent before and after light incubation, respectively. Data from three independent experiments. F, Elemental x-ray microanalysis shows change in K⁺ as a weight percent of seven elements (K, Ca, Cl, Mg, Na, O, and P) in guard cells of vector controls and transgenic K⁺_in channel depressor line numbers 15-4 and 22-6. Leaves were harvested 10 min prior to illumination and at 30 min after onset of illumination. Black bar and white bar represent before and after light incubation, respectively. Each value is the mean ± se from 30 guard cells, 10 each from three separate leaves.