Fig 4. SO₂ enhances the activities of free and bound forms of β-amylase, and of α-amylase in embryoless barley grains.

(A) shows native PAGE analysis of the activity of free form β-amylase in embryoless barley grains treated with different concentrations of SO₂ donor for 9 h and (B) native PAGE analysis of bound form β-amylase activity. SO₂ donor at 0.8 mM is applied to bound form β-amylase for 0, 3, 6, 9 and 12 h and the activity is shown on native PAGE (C). Embryoless barley grains are incubated with different concentrations of SO₂ donor plus 20 μM GA₃ for 48 h and α-amylase activity in incubation medium surrounding the aleurone layers is visualized by native PAGE (D). (E) shows secreted α-amylase activity in incubation medium surrounding embryoless half seeds treated with 20 μM GA₃ + H₂O (CK) or 20 μM GA₃ + 1 mM SO₂ donor (T) at different times of incubation. Data in (E) are expressed as means ± SD of three independent experiments with three replicates of 20 embryoless half grains per treatment.