CHANGES IN PEROXIDASE-ACTIVITY AND IN PEROXIDASE ISOZYMES IN CARROT CALLUS

Activity of soluble peroxidase and its isozyme patterns in carrot (Dau cus carota L.) callus after excision and transfer to fresh Murashige a nd Skoog (MS) culture medium was investigated. The activity decreased markedly until day 1 and then increased gradually during days 7-10 at room temperature. The rapid initial decrease of the activity was also observed at low temperature (2-degrees-C) as well as in the presence o f cycloheximide. However, the subsequent increase in the peroxidase ac tivity after day 1 was slower at low temperature than at room temperat ure, and was not detected in the presence of cycloheximide. Activity o f catalase decreased slightly within 4 days and cycloheximide enhanced the decrease of the activity. Two cationic and one anionic peroxidase isozymes disappeared or decreased markedly within the first day and o ne cationic and anionic peroxidase recovered 3-6 days after excision.