Changes in the antioxidant system in response to exogenous ethylene during development in 'Maroussia' cut rose (Rosa hybrida)

As rose is an important cut flower understanding the effects of ethylene on the display life of roses (Rosa × hybrida) was considered important. In this study the activities of antioxidant enzymes were characterized during rose flower bud development and opening. Floral stems of the rose cultivar ‘Maruossia’ were harvested from a commercial greenhouse at 2 stages of flower opening, either as a partially opened bud or fully open. Flowers were either exposed to 8 μL L^‑1 ethylene for between 24 and 48 h or without ethylene, as a control treatment. The activities of catalase (CAT) and peroxidase (POX) increased when harvested at the bud stage after 24 h. The activity of CAT gradually increased at the open stage at 48 h after ethylene treatment. A significant decline in total superoxide dismutase (SOD) activity was observed when harvested at the open stage at 48 h after the ethylene treatment, supporting the hypothesis that loss of SOD can enhance damage against by O₂. Higher POX activity than CAT suggests that POX can serve as a better intrinsic defense tool to resist ethylene damage at the open stage.