CYCH;1 regulates the stomatal aperture under blue light. Stomatal density (A) and stomatal index (B) of wild-type and cych;1 RNAi plants. Data are means ± se. C, Stomatal closure in wild-type and cych;1 RNAi plants in response to various concentrations of ABA. D, Stomatal aperture under different light conditions in wild-type, cych;1 RNAi, cry1, and cry2 plants (*P < 0.05 and **P < 0.01, Student’s t test). E, Four-day-old seedlings of Col-0 and cych;1 RNAi mutants were grown under 10 μmol m–2 s–1 blue light or in darkness. F, Blue light response of Col-0 and cych;1 RNAi. The y axis represents the length of hypocotyls grown in blue light relative to that of hypocotyls grown in darkness. Data are means ± sd. [See online article for color version of this figure.]