Norflurazon treatment of adult plants leads to narrowed branch tip angles and decreased TAC1 expression. (A) Phenotypes of Col and tac1 mutant adult Arabidopsis plants watered with NF or mock control after 4 d of growth. (B) Quanitification of branch tip angles in Col and tac1 adult plants with NF or mock control. (C) TAC1 expression in apices of Col plants treated with NF or mock control. Expression is decreased when treated with NF.