A RELATIONSHIP BETWEEN ASCORBATE PEROXIDASE-ACTIVITY AND THE CONVERSION OF 1-AMINOCYCLOPROPANE-1-CARBOXYLIC ACID INTO ETHYLENE

In three plant materials as different as Acetabularia algae, mung bean hypocotyl and sugar beet callus, ascorbate peroxidase activity was found the highest in the fast growing stages, zones or conditions, with a decreasing gradient along with slower growing phases. In each material, there was a close similarity between ascorbate peroxidase activity (measured in extracts) and the capacity of the intact tissues to convert ACC into ethylene. Because ascorbate peroxidase activity is associated with mitochondria metabolism and with redox reactions at the plasma membrane level, two sites where EFE activity takes place, the direct or indirect role of ascorbate peroxidase in the ACC-oxidase system might be assumed.