Effect of spermidine and application on internal polyamine content, free radical enzyme activity and lipid oxidative destruction in cut ‘Black Magic’ rose flowers.

Rose is one of the most important ornamental plants which nowadays holds the first top position in production and export of cut flowers due to its beautiful and colorful flowers. The quantity and quality of rose cultivars depend on environmental and nutrition. Pre and post-harvest application of plant growth regulators is one of the common methods for quality improvement of this flower. Therefore, in the present study, cut ‘Black Magic’ rose flowers were treated at pre harvest with spermidine (0, 50 and 100 mgl-1) and with salicylic acid (0, 50 and 100 mgl-1) during postharvest. Consequently, postharvest quality from various point of view such as internal polyamine content, activity of free radical enzymes (such as superoxide dismutase, catalase and polyphenol oxidase) and destructive lipid oxidation (malondialdehyde content) were studied. Results indicate that foliar application with spermidine and with salicylic acid increases petal soluble protein content, improves the activity of superoxide dismutase, catalase and poly phenol oxidase in the petals of cut ‘Black Magic’ rose flowers. Activity increment of enzymes that are involved in oxidative stress, decreased lipid peroxidation and consequently, they decreased malondialdehyde content as destructive biomarker. Internal polyamines such as spermine, spermidine and putrescine were also significantly affected by spermidine and salicylic acid application.