Effects of various inhibitors on changes in cytosolic Ca²⁺ induced by BL in the Arabidopsis wild type (WT) and phot1 and phot2 mutants. A single seedling, treated with each inhibitor in the dark for 1 h, was irradiated with 100 μmol m⁻² s⁻¹  BL for 15 s. A, Effects of 2 mm EGTA. B, Effects of 1 mm LaCl₃. C, Effects of 10 μm U-73122 (10 μm U-73343, an inactive analog, was used as the control). D, Effects of 20 μm  RR. Error bars indicate the se of five to 10 independent experiments.