Figure 6.

Timing of GA₅ export from a treated leaf to the shoot apex as shown either by increase in the floral response of the shoot apex with increasing time until removal of the GA-treated leaf blade, or by arrival at the shoot apex of [²H₄] GA₅ following its application to the leaf. In both treatments, a dose of 25 μg of GA was applied to the leaf blade 6 h after the start of the main light period prior to the single LD extension. Values for floral apex length are the means and se. Plants not treated with GA₅ flowered to the same extent as those with the treated leaf removed at the start. There was only a trace of [²H₄] GA₅ detected at the apex after 24 h, but it is shown in brackets because there was uncertainty about quantitation of the gas chromatography (GC)-MS peak for the [²H₂] GA₅ internal standard.