Figure 4.

Influence of GAs on seed germination of the tt2-1 Arabidopsis mutant in the presence or absence of α-amanitin. A, Germination curves. Seeds were incubated on water (○), water plus 100 μm GA₄₊₇ (▵), water plus 100 μm PAC (⋄), water plus 100 μm PAC and 100 μm GA₄₊₇ (□), 500 μm α-amanitin (•), 500 μm α-amanitin plus 100 μm GA₄₊₇ (▪), and 500 μm α-amanitin plus 100 μm PAC (♦), and germination was scored by the frequency of radicle protrusion through the seed coat. The figure shows a typical experiment repeated three times in triplicate; errors bars are of the size of the symbols. B, Influence of α-amanitin on the sensitivity to GAs of tt2-1 seed germination. Seeds of the tt2-1 mutant were incubated in the presence of 100 μm PAC, various concentrations of GA₄₊₇ as indicated on the plot, and in the presence (•) or absence (□) of 500 μm α-amanitin. Germination was scored 43 and 127 h after sowing for the seeds incubated in the absence or presence of α-amanitin, respectively. The figure shows a typical experiment carried out two times in triplicate.