Peroxidase (POD, EC 1.11.1.7) activity was assayed as
described by Lu¨ck (1962), with p-phenylodiamine and
H2O2 used as the enzyme substrates. Two and-a-half grams
of fresh plant leaves were ground in an ice bath with
0.05 M potassium phosphate buffer. The ground material
was centrifuged (3492g, 15 min, 4 C). The reaction mixture
consisted of diluted supernatant, 0.05 M potassium
phosphate buffer, p-phenylodiamine, and H2O2 solution.
Absorbance was measured at 485 nm at 60-s intervals for
2 min on a UV–VIS Helios Beta spectrophotometer.
Activity of POD was presented in micromoles H2O2 per
1 min per 1 g FM.