A rapid chronometric assay of peroxidase activity in citrus leaf discs

Abstract A rapid peroxidase assay is proposed, using 3-mm diameter leaf discs, and based on the chronometric measurement of the oxidation of ascorbic acid, which is detected by means of the appearance of the blue colour of the benzidine-coupled reaction. The proposed method is adequately reproducible and sensitive for the diagnosis of iron deficiency in citrus.