Figure 4.
Ethylene produced by wild-type and mutant etiolated Arabidopsis seedlings in response to treatment with ABA (75 μm), 2,4-D (160 μm), BA (5 μm), CuSO4 (20 mm), and 1 μm 24-epibrassinolide (24-epi). For all treatments except BA, seedlings were grown in GC vials, and 200 μL of the solutions of the indicated concentrations was added at 48 h. The vials were flushed with hydrocarbon-free air, sealed, and returned to the dark at 23°C. The ethylene that accumulated during the next 24 h was measured. For BA treatment, the seedlings were germinated on Murashige and Skoog medium supplemented with 5 μm BA and the ethylene production during the first 72 h of germination was measured. Values are means (±sd) of three replicates.