Effect of pre-harvest application of promalin and 1-MCP on preservation of cut lily and its relationship to energy metabolism

Lilies (Lilium spp.) are in demand worldwide because of their superior commercial and ornamental value. To develop new and practical preservation technologies, effects of pre-harvest treatment of Promalin (a.i. 1.8% each of 6-benzyladenine (6-BA) and gibberellic acid (GA4 + 7)) and 1-Methylcyclopropene (1-MCP) on cut lily under cold storage were investigated. Oriental lily ‘Sorbonne’ was selected for this study. The field plants at coloring stage were sprayed with 25 mg L−1 Promalin, 30 μL L−1 1-MCP additionally, their combination (1-MCP + Promalin) was also tested. Deionized water was used as control. The flower stems were harvested 24 h later and stored at 3 ± 1 °C. Preservation effect and physiological changes, e.g. inflorescence life, flower life, opening rate, dry weight loss rate, respiration rate, ethylene production rate, malondialdehyde (MDA) content, lipoxygenase (LOX) activity, energy metabolism related indexes including adenosine triphosphate (ATP) content, energy charge, activities of ATP synthase (ATPase), succinate dehydrogenase (SDH), cytochrome oxidase (CCO) and Ca2+-ATPase were determined. The results showed that 1-MCP or Promalin treatment extended the vase life of stored cut lilies and inhibited the decline of the dry weight of petals, reduced respiration rate, ethylene production rate, LOX activity and the accumulation of MDA. They also maintained the activity of ATPase, Ca2+-ATPase, SDH, CCO, ATP content and energy charge of cut lilies at a higher level than control. 1-MCP + Promalin exhibited an additive effect. Combination treatment maintained the flower opening ability as high as 89.3% after five-week storage, control merely maintained it till 3 weeks. These data indicate growth regulators (e.g. 1-MCP or Promalin) can extend the storage life of cut lily ‘Sorbonne’ through cutting down respiration consumption and manipulation of energy balance.