Improved Histochemical Test for In Situ Detection of Hydrogen Peroxide in Cells Undergoing Oxidative Burst or Lignification

An improved version of a simple histochemical test for the in situ assaying the production of hydrogen peroxide in living plant tissue was demonstrated. The test solution containing 50 mM KI in a 4 % potato starch solution was directly applied to the fresh cut surface of the tissue to be tested. Incorporation of an enhancer potassium permanganate (1 % final concentration) into the test reagent resulted in a ten times greater hydrogen peroxide mediated oxidation of iodide ions to iodine, especially in the case when, e.g. suboptimal concentration of H2O2 is present or endogenous catalase decomposes the H2O2 in tissue as quickly as it is evolved. Subsequently, iodine is complexed by the starch to form a coloured product. H2O2 production by wound-induced oxidative burst or lignification can be easily discriminated due to the dual colour response.