Role of Flower Preservative Solutions During Postharvest of Hydrangea macrophylla cv. Bela
Hydrangea macrophylla (hydrangea) is widely used as an ornamental plant and cut flower due to its inflorescence, which is composed of colored bracts. As cut flowers, hydrangeas show a postharvest life of up to 1 month at 2 °C, but little is known about their postharvest life during air shipment. This study was aimed at evaluating the effect of Triton X-100 (surfactant) and ClO2 (biocide) during an air shipment simulation of hydrangea harvested at two floral stages of development: fresh and antique. Vase life, fresh weight loss (FWL) and solution uptake were evaluated after an air shipment simulation. Furthermore, bacterial counts and microscopic observation of the bracts were performed in order to understand the water relations of hydrangea during vase life. The longest vase life was observed in antique hydrangeas, and the control (deionized water) was the best treatment, reaching up to 32.7 days in this floral stage. FWL was faster when using Triton X-100 (3.83 days to lose 20% of FW) compared to deionized water (8.75 days). However, this flower preservative was efficient at promoting solution uptake (31.96 mL). Bacterial plugging did not appear to occur considering that the high presence of microorganisms counted did not affect solution uptake or vase life. The presence of stomata on the bracts seems to be crucial for the dehydration of the inflorescence, a problem that was not solved by the higher water uptake promoted by Triton X-100. Thus, deionized water was the best treatment, and the effect of flower preservatives in order to extend vase life of hydrangea cut flowers was insignificant.