Influence of eucalyptus oil, humic acid and chemical preservative solutions on vase life and physiological characteristics of calla (Zantedeschia aethiopica R.) cut flowers

The calla lily cut flower (Zantedeschia aethiopica cv. ‘Romance’), with a white spathe, is a significant ornamental flower. There is a growing interest in developing cost-effective and eco-friendly preservative solutions to extend vase life. The Ornamental Plants and Landscape Gardening Research Department, Horticulture Research Institute, Giza, Egypt, conducted this study in the postharvest laboratory during the 2020 and 2021 to examine the effects of various holding solutions, both individually and in combination, including distilled water (DW) as a control, eucalyptus oil (EO) at concentrations of 1 and 2 mL/L, humic acid (HA) at 25 and 50 mL/L, sucrose (Suc) at 20 g/L, 8-hydroxyquinoline citrate (HQ) at 0.2 g/L, citric acid (CA) at 0.2 g/L, and gibberellic acid (GA3) at 0.05 g/L. The results showed that all holding solutions significantly improved the measured characteristics compared to distilled water. It’s worth mentioning that putting cut flowers in a solution with humic acid at 25 mL/L, either alone or with sucrose at 20 g/L and citric acid at 0.2 g/L, made the flowers last longer, look better, and have higher flower fresh weight (IFFW%), relative fresh weight (RFW%), water uptake rate (mL), and total carbohydrate content (%). During both seasons, humic acid (50 or 25 mL/L) as a single treatment yielded the highest phenol content followed by eucalyptus oil (2 mL/L).