Figure 5.

HID1 promotes phyB-dependent seed germination by repressing ABA biosynthesis. A, Representative images of WT, hid1, and two genetic suppressor lines of hid1 (4A2 and 43A1) following 48 h DAL under phyB-on conditions. Scale bar, 1 mm. The table underneath shows mutational information for the HID1 suppressor genes. B, Germination rates of WT, hid1, and four genetic suppressor lines of hid1 (4A2, 43A1, 81A2, and 547A1) following 48 h DAL under phyB-on conditions. Germination frequencies were recorded every 24 h after light treatment. Mean ± SD, n = 3. C, Germination rates of WT, hid1, aba3-1, and the hid1 aba3-1 double-mutant following 48 h DAL under phyB-on conditions. Mean ± SD, n = 3. D and E, Quantitation of endogenous ABA (D) and GA₄ (E) levels in WT and hid1 mutant seeds following 48 h DAL under phyB-on conditions. FW, fresh weight. Mean ± SD, n = 4. ** P ≤ 0.01, *** P ≤ 0.001 (two-tailed Student's t-test). F and G, Germination rates of WT and hid1 mutant seeds exposed to different chemical treatments. CK, no chemical treatment; FLU, Fluridone; GA, GA₃. Mean ± SD, n = 3.