JA responsiveness of hy1 hy5 d ouble mutants. A, Quantification of root length of 16-day-old wild-type and hy1 mutant plants grown in constant WL (90 μmol m-2 s-1) without hormone (JA). B, Quantification of root length of A. C, Relative induction of VSP2 expression by JA in wild-type and mutant plants. Six-day-old wild-type and mutant seedlings were treated with MS (Mock) or with JA (50 μM) for 5-hours and total RNA was isolated from 100 mg of tissue and used for quantitative real-time PCR analysis. ACTIN2 was used as internal control. Approximately 25 to 30 seedlings were used for the root growth measurement. The error bars indicate standard error (SE) of three biological replicates.