Seasonal changes in leaf and twig antioxidant systems in Damask rose (Rosa damascena Mill.)

The present study aimed to investigate the antioxidant activity of the various tissue types in Rosa damascena and determine the seasonal variations. The existence of statistically significant differences in the specific activities of enzymes among R. damascena accessions and tissue type was observed annually. The content of enhanced peroxidase and catalase in leaves has been shown to undergo seasonal changes with relatively low levels on young leaves in spring and strong activities on mature leaves in autumn. Meanwhile, the expansion of season from spring to winter showed a decrease in twig peroxidase activity, but catalase activities enhanced before raining in the autumn and then it decreased. Based on the results, R. damascena tissues, such as leaves and twigs indicated different responses including activation of antioxidative enzymes to seasonal change and during acclimatization to environment. There were significant differences in the specific activities of enzymes among R. damascena accessions.   Key words: Antioxidant activity, catalase, enzyme, harvesting time, peroxidase seasonal changes.