Changes in activities of superoxide dismutase, catalase and peroxidase during senescence of gladiolus florets

Treatments with sodium benzoate and n-propyl gallate as free, radical scavengers slightly:delayed the wilting of perianth in detached gladiolus florets; Superoxide dismutase (SOD) activity of the perianths sharply decreased in 2 days after their full unfolding (DAU) when they commenced to wilt. The decrease of SOD activity was alleviated by treatments with 300 mu M cycloheximide (CHI) which prevented perianths from wilting. specific activity of catalase (CAT) of perianths did not markedly change, but CAT activity on the basis of perianth decreased concomitant with their wilting. CHI slightly decreased specific activity of CAT. Peroxidase (POD) activity of the perianths sharply increased 1 DAU. This; increase was almost completely suppressed by CHI treatments. These results indicate that the free radicals are involved with the decline of SOD activity, increase of POD activity, and in the wilting process of gladiolus perianths.