Effects of BA and TDZ on postharvest quality and expression of laccase and aquaporin genes in cut rose ‘Sparkle’

• We tested two cytokinins (TDZ & BA) which regulated the gene expression and affected flower longevity.
• Cytokinins interact with other plant hormones in delaying senescence and extending plant organs longevity
• TDZ was better than BA and increased flower longevity 2 days in compared to control (no treatment).
• BA decreased the longevity of flowers concomitantly with appearing necrosis symptom on petals.
• BA induced the expression of RhLAC gene, while TDZ had no significant impact on RhLAC transcription expression level.

This experiment was conducted to study the effects of BA and TDZ on postharvest quality of cut rose ‘Sparkle’ and expression of Laccase and Aquaporine genes. The concentrations of TDZ at 25 and 75 μM and BA at 150 and 300 μM were applied for 24 h as pulsing, while control cut roses received neither TDZ nor BA. TDZ with 25 and 75 μM increased the longevity of flowers 1 and 2.8 days respectively, compared to control. Furthermore, TDZ in both concentrations showed significant difference in flower quality. 150 μM BA showed less adverse effects on display quality than 300 μM BA. In fact, applying 300 μM BA resulted in early petal senescence and bent neck. Expression patterns of Aquaporin (RhTIP), and Laccase (RhLAC) genes were investigated in leaves received 75 μM TDZ and 150 μM BA, as well as control treatment. The result showed that 150 μM BA induced the expression of RhLAC gene, while TDZ had no significant impact on RhLAC transcription expression level. Expression of RhTIP was neither affected by BA nor by TDZ. These results suggest that decline of postharvest quality and increase in the expression of RhLAC under BA treatment could be related to BA-induced stress affecting the endogenous ethylene production in cut rose cv. Sparkle. In contrast to TDZ which prolonged postharvest quality of cut rose cv. Sparkle, BA decreased the longevity of flowers concomitantly with appearing necrosis symptom on petals.