Iron and Copper Enzymes in Leaf Lamina of Tobacco When Deficient in Micronutrients or Grown on Calcareous and Organic Soils

Abstract

In determinations of comparative enzymatic activities for ascorbic acid oxidase, catalase, and peroxidase in Connecticut Broadleaf tobacco deficient in specific micronutrients (water cultures), each type of deficiency exhibited a characteristic enzymatic pattern of the leaf lamina. Tobacco grown on a calcareous soil (lime-induced chlorosis) gave the same type of enzymatic pattern as on Fe-deficient nutrient solutions. Likewise, plants grown on the Cu-deficient organic soil gave the same type of enzymetic pattern as those grown on Cu-deficient nutrient solutions. Fe-deficient plants had a relatively lower peroxidase activity than B and Zn-deficient plants. Catalase activity was comparatively low in all 3 of these deficiencies. Mn-, Mo-, and Cu-deficient plants showed a comparative decrease in ascorbic acid oxidase activity. The decrease was greatest in the Cu-deficient plants which had the highest catalase activity. Peroxidase activity appeared to be much higher in the Mn-deficient plants than in either of the other 2 deficiencies. Some of the enzymatic patterns characteristic of the individual micronutrient deficiencies appeared in the leaves prior to or in the absence of the formation of visible symptoms.