Optimal Postharvest Handling Protocols for Antirrhinum majus 'Chantilly Yellow' and Celosia Cristata 'Fire Chief'

Snapdragon (Antirrhinum majus L.) and celosia (Celosia cristata L.) are commercially important specialty cut flowers, but postharvest handling protocols for extending vase life need to be optimized. Stems of snapdragon harvested when the lowermost florets started expanding, had 3.4 days longer vase life than stems harvested with three or more florets open at harvest, while celosia stems harvested when the flower heads were < 2 cm in diameter, had 14.0 days longer vase life than stems harvested with flower heads > 5 cm at harvest. However, visual quality of later harvested stems for both species was higher than early harvested stems. Harvest procedures, exogenous ethylene, and commercial hydrators had no effect on longevity of both species. For celosia, anti-ethylene agents also had no effect, however, for snapdragon, the anti-ethylene agent, silver thiosulfate, increased vase life 3.2 or 3.7 days longer than deionized (DI) water or 1-methylcyclopropene (1-MCP), respectively. Dry-stored stems of snapdragon had longer vase life compared with stems stored in water, for not more than 2 weeks, whereas, celosia stems did not tolerate storage at 4 ±1 °C irrespective of the storage methods, and if necessary, should only be stored in water, for not more than 1 week. Use of both hydrator and/or holding preservatives did not result in significant differences in vase life of both species; however, pulsing with 5% or 10% sucrose supplemented with the antimicrobial agent, Kathon (7 mg·L^-1), for 24 hours doubled vase life of snapdragon stems and increased flower bud opening and fresh weight of stems during the vase period. Stems of snapdragon kept continuously in commercial preservatives had 2-fold longer vase life than stems in DI water. Floral foam reduced vase life of snapdragon when saturated with preservatives, or had no effect when saturated with DI water. Stems of celosia kept continuously in Floralife Clear Professional Flower Food with or without floral foam had longer vase life compared with Chrysal Clear Universal Flower Food or foam saturated with DI water.