Enzymatic Auxin Inactivation by Extracts of the Fern, Osmunda cinnamomea L.

Abstract

An enzyme system which inactivates auxin at cut surfaces and in crushed tissue extracts of fronds of the fern 0. cinnamomea is described. Its activity in extracts of different tissues, and extracts of leaves of different ages is noted. Rhizome extracts fail to destroy auxin. The system is heat labile, involves a heavy metal, probably iron, and requires oxygen. Results obtained from the addition of H2O2 to the system suggest that a peroxidase is involved. Variations in catalase and peroxidase activity in extracts from developing fronds are described, and evidence suggesting an inhibitor of auxin inactivation is presented. These factors may be partially responsible for variations observed in auxin destruction by extracts of fronds of different ages, and extracts of different parts of single fronds.