Abstract:

In this work, we investigated roles of endoproteases (EP) and main anti-oxidant enzymes in water deficit stress (WDS)-induced senescence in cut roses. Our results showed that 24 h WDS shortened vase life by 16.4% and 36.9% in ‘Sunny leonidas’ and ‘Sun stone’, respectively. WDS increased MDA content and the activity of anti-oxidant enzymes, including SOD (superoxide dismutase), catalase (CAT) and peroxidase (POD) in leaves and petals of both cultivars. WDS also enhanced activities of metallo proteinase, thiol proteinase and serine proteinase. When water available (WA), morphological appearance of ‘Sunny leonidas’ was restored better than ‘Sun stone’. Compared to the latter, ‘Sunny leonidas’ had lower MDA content of leaves and petals and delayed increase in activities of all three anti-oxidant enzymes. Serine proteinase was a major EP during WA in both cultivars, however its activity increased more rapidly and sharply in ‘Sun stone’ than in ‘Sunny leonidas’. It was suggested that anti-oxidant enzymes and EP were involved in the response of cut roses to WDS, and serine proteinase might be the major EP functioned in WDS.

Key words: rose, cut flower, water deficit stress, anti-oxidant enzymes, endopeptidase