The Impact of Deficit Irrigation on the Postharvest Vase Life of Cut Delphinium ‘Guardian Blue’ Flowers

Minimizing postharvest water loss through stomata may delay wilting or senescence in cut flowers. Drought stress induces stomatal closure and decreased transpiration rates as plants try to minimize water loss. Subjecting cut flowers to drought stress during production may also limit postharvest water loss, thus extending vase life. The objective of this study was to investigate the postharvest impacts of drought stress on delphinium (Delphinium elatum L.) ‘Guardian Blue’ cut flowers. Delphinium 'Guardian Blue' plants were grown in soilless media in a greenhouse. After flower bud initiation, delphinium plants received sufficient irrigation (control), moderate or severe water deficits. Deficit irrigation was applied by measuring the volumetric water content (VWC) of the substrate once daily. Mean daily VWC for the control, moderate deficit, and severe deficit treatments were 20.0±0.4%, 18.2±0.4%, and 14.5±0.5%, respectively. Moderate or severe water deficits did not change pre- or postharvest stomatal conductance or transpiration of delphinium ‘Guardian Blue’ cut flowers. Deficit irrigation did not extend vase life of delphinium ‘Guardian Blue.’ Growers may be able to reduce water use during production of delphinium ‘Guardian Blue’ cut flowers without adversely impacting postharvest longevity.