Chitooligosaccharide-induced activation of o-phenylenediamine oxidation by wheat seedlings in the presence of oxalic acid.

A method for determination of oxidation of phenolic compounds by intact wheat seedlings using o-phenylenediamine (OPD) was developed. The reaction is initiated by the addition of oxalic acid to the incubation medium. It is suggested that an endogenous peroxidase and hydrogen peroxide formed during oxidation of oxalic acid by endogenous oxalate oxidase are involved in OPD oxidation. Treatment of plants with chitooligosaccharides (1-10 mg/liter) with acetylation degree of 65% and molecular masses of 5-10 kD significantly activated OPD oxidation by wheat seedlings.