Optimal postharvest handling protocols for Celosia argentea var. cristata L. 'Fire Chief' and Antirrhinum majus L. 'Chantilly Yellow'.
Celosia (Celosia argentea var. cristata L.) and snapdragon (Antirrhinum majus L.) are commercially important specialty cut flowers, but postharvest handling protocols for extending vase life need to be optimized. Stems of 'Fire Chief' celosia 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, while 'Chantilly Yellow' snapdragon stems harvested when the lowermost florets started expanding had 3.4 days more vase life than stems harvested with three to five florets opened at harvest. However, visual quality of later-harvested stems of both species was higher than early harvested stems due to showier, larger flower celosia heads and a greater number of total florets of snapdragon spikes opened during the vase period. Harvest procedures, exogenous ethylene, anti-ethylene agents, and commercial hydrators had no effect on longevity of both species except silver thiosulfate, an anti-ethylene agent, increased vase life of snapdragon 3.2 or 3.7 days more than deionized (DI) water or 1-methylcyclopropene, respectively. Stems of celosia did not tolerate storage at 3±1°C, irrespective of the storage method, and if necessary, should only be stored for ≤1 week in water. On the other hand, snapdragon stems could be dry-stored for 2 weeks with no decrease in vase life and had a longer vase life than stems stored in water. Pulsing with 5 or 10% sucrose supplemented with the antimicrobial agent, isothiazolinone at 0.007 mL L-1, for 24 h, and use of hydrator for 4 hours and/or holding preservatives for 44 h reduced vase life of celosia stems compared to DI water. Whereas, use of both hydrator for 4 h and holding preservatives for 44 h did not result in significant differences in vase life, but pulsing with 5 or 10% sucrose supplemented with the antimicrobial agent, isothiazolinone at 0.007 mL L-1, for 24 h doubled vase life of snapdragon stems and increased flower bud opening and fresh weight of stems during the vase period. Celosia stems 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, while snapdragon stems kept continuously in commercial preservatives had 2-fold longer vase life compared with DI water. Floral foam reduced vase life of snapdragon when saturated with preservatives, or had no effect when saturated with DI water. Vase life and quality of both 'Fire Chief' celosia and 'Chantilly Yellow' snapdragon stems can be extended by following appropriate postharvest handling procedures.