Fig. 2.

Measurement of antioxidant enzyme activities in control (C) and YK1-overexpressing callus (L-1). Catalase (CAT), ascorbate peroxidase (APX) and glutathione peroxidase (GPX) were measured using H₂O₂ as a substrate. Activities are expressed as relative activity (%) of the control. Exact values of activities in control calli are 65·8 (μmol H₂O₂ reduced min⁻¹ mg protein⁻¹) for CAT, 66·1 (nmol ascorbate oxidized min⁻¹ mg protein⁻¹) for APX, 101·0 (nmol NADPH reduced min⁻¹ mg protein⁻¹) for GPX and 95·1 (nmol NADPH reduced min⁻¹ mg protein⁻¹) for glutathione reductase (GR). All data represent the mean of three independent experiments.