GA structure-activity relationships
| GA-a | Hypocotyl Length-b | GA4:APT1Ratio-c | Activity-d |
|---|---|---|---|
| mm | |||
| 3β-OH-GAs | |||
| 0 | 0.8 (0.1) | 1.00 | — |
| GA4 | 3.3 (0.3) | n.d.-e | Active |
| GA1 | 1.0 (0.1) | 0.41 | Inactive |
| GA4-Methyl ester | 0.7 (0.1) | 0.80 | Inactive |
| GA C | 0.9 (0.1) | 0.98 | Inactive |
| Non-3β-OH-GAs | |||
| epi-GA4 | 2.8 (0.3) | n.d. | Active |
| 3-oxo-GA9 | 4.1 (0.4) | n.d. | Active |
↵F0-b Seedlings were grown on germination medium containing individual GAs or analogs at 10−7 m. Hypocotyls were measured as described in Figure 2 withse in parentheses.
↵F0-c RelativeGA4 transcript levels calculated after 22 cycles.GA4 and APT1 transcript levels were obtained initially as ImageQuant phosphor imaging values (see Methods), and are expressed as normalized GA4:APT1 ratio (gal-3 grown on germination medium only = 1).
↵F0-d Activity of each GA at 10−7 m. GA1, although classed here as inactive, has mild activity.
↵F0-e n.d., Samples where the GA4transcript level was too low to be detected, preventing calculation of the GA4:APT1 ratio. In all cases APT1 was expressed at a similar level.