Figure 8.

Regulation of Arabidopsis GA20ox2, GA2ox4, and GA2ox1 Expression by GA in Arabidopsis.

(A) and (B) Seedlings of wild-type Col-0 and dellaP mutant Arabidopsis plants were treated with PAC (5 mg/L) once a day for 3 d followed by a single GA₃ application (10 μM). Three hours after the GA treatment, RNA was extracted from the seedlings and analyzed by qRT-PCR for At-GA20ox2 (A) and At-GA2ox4 (B) expression.

(C) to (E) Plants (wild-type Col-0 and dellaP) were treated with PAC (5 mg/L) twice a week until flowering and then treated once with 10 μM GA₃. Three hours after the GA treatment, RNA was extracted from the flowers and analyzed by qRT-PCR for At-GA20ox2 (C), At-GA2ox4 (D), and At-GA2ox1 (E).

(F) Wild type (Col-0) and gid1ac seedlings were treated with PAC (5 mg/L) once a day for 3 d followed by a single GA₃ application (10 μM). Three hours after the GA treatment, RNA was extracted and analyzed (qRT-PCR) for At-GA2ox4 expression.

Values (gene-to-TUBULIN ratios) in (A) to (F) are means of three biological replicates ± se.