PEROXIDASE ISOENZYMES IN NORMAL AND HABITUATED CALLI OF SUGAR-BEET DURING TRANSFER FROM LIGHT TO DARKNESS

Habituated sugar beet calli have been characterized as having a defici ency in some tetrapyrrole containing compounds. However, peroxidases m ight be dissociated from the other tetrapyrrole containing compounds. When light-cultured normal and habituated calli were transferred to da rkness their peroxidase activity reduced and increased respectively, i ndicating that habituation could not strictly be characterized by a de ficiency in peroxidase content but rather by a different regulation of Its activity. This regulation could be mediated through soluble effec ters which act as potential peroxidase inhibitors and/or by a differen tial expression of the peroxidase isoenzyme patterns which were presen t in these tissues in both light and darkness, The different peroxidas e activity and the nature of acidic and basic peroxidase isoenzymes in normal and habituated tissues could explain the different features of both types of cultures.