How to assay the Peroxidase activity?

Peroxidase influences plant growth through lignin synthesis , oxidative coupling reactions involving phenolics that are esterified to cell wall polysaccharides . An inverse relationship between growth rate and POD activity has been reported in many plant systems. Thus POD is generally believed to be a putative wall rigidification enzyme. Peroxidase assay is done to determine the changes in cell-wall peroxidase (POD) activity and H2O2 level in roots of NaCl-stressed rice seedlings and it was discussed in this video.Both ionically bound and covalently bound cellwall PODs were present in cell walls of rice roots.Increasing concentrations of NaCl from 50 to 150 mM progressively reduced root growth and increased ionically bound cell-wall POD activity,but NaCl had no effect oncovalently bound cell-wall POD activities. The reduction of root growth by NaCl is closely correlated with the increase in H2O2 level. Exogenous H2O2 was found to inhibit root growth of rice seedlings.