Figure 4.
Exogenous GA promotes testa rupture by downregulating DELLA protein levels without overcoming ABA-dependent blockade of endosperm rupture. (A) Protein gel blot analysis of GAI, RGA, RGL2 and ABI5 protein levels in ga1-3 seeds at the indicated times upon imbibition under white (W) or far-red (FR) light conditions in the presence of 3 μM ABA without (ABA) or with 50 μM GA (ABA+GA). Each lane contains proteins extracted from 5 mg of seeds. (B) Representative pictures showing ga1-3 seeds after 5 days under white (white) or far-red (FR) light conditions in the presence of 3 μM ABA without (ABA) or with 50 μM GA (ABA+GA). Arrows indicate testa rupture event. Histogram shows percentage of testa and endosperm rupture events at this time point (in three independent seed batches (n=150–300) testa rupture percentage is always either 0 or 100% depending on the genotype and the light conditions as shown in the histogram).