Fig. 1
HCO3−-induced [Ca2+]cys increase in Arabidopsis leaves and guard cells. a HCO3−-induced [Ca2+]cys increase in Arabidopsis leaves. (Left) AEQ-transgenic Arabidopsis leaves were treated with 1 mM KHCO3, and analyzed by AEQ imaging at 0 and 5 min. (Right) Time-course analysis of [Ca2+]cys changes after treatment with incubation buffer, 1 mM KCl and 1 mM KHCO3. Leaves were put individually into the wells of a 96-well plate and treated with incubation buffer, 1 mM KCl or 1 mM KHCO3. Luminescence recording began 4 s before treatment and was conducted at intervals of 0.2 s for a total of 12.4 s. Data for 59 leaves are shown (mean ± SE; n = 59). Bar = 5 mm. RLU, relative luminescence units. b HCO3−-induced [Ca2+]cys increase in Arabidopsis guard cells. (Left) AEQ images of AEQ-transgenic Arabidopsis epidermal strips after 1 mM KHCO3 treatment. Red circles indicated guard cells. (Right) Time-course analysis of [Ca2+]cys changes after 1 mM KHCO3 treatment. The luminescence data were quantified from guard cell pairs (red circles) in the left side of the figure (n = 8). Bar = 20 µm. c Emission images (FRET-dependent Venus, 526–536 nm; CFP, 473–505 nm) of epidermal strips expressing YC3.6 were taken before and 1 min after addition of 1 mM KHCO3 solution. Bar = 10 µm