Prevention of stem-base splitting in cut Zantedeschia aethiopica flowers by pulsing with salt solutions
Stem-base splitting is a postharvest problem in several geophyte cut flowers, including Zantedeschia aethiopica. This phenomenon interferes with the flower packaging, and negatively affects the flower appearance during marketing and vase life due to the upward curling of the stem edges. A partially effective solution to prevent this problem was previously reported, using sucrose pulsing with the preservative 8-hydroxyquinoline citrate (8-HQC). However, this combination did not improve spathe longevity, and enhanced leaf senescence of cut Z. aethiopica flowers. The purpose of the present study was to develop an alternative treatment for preventing stem-base splitting. Our results show that pulsing the stems for 24 h with salts, such as 0.3% NaCl, 0.37% KCl or 0.5% CaCl2, completely prevented the problem in cut Z. aethiopica flowers without causing any adverse effects. Distilled water significantly aggravated the stem-base splitting compared to tap water, while the type of salt had no effect, provided that its concentration was at least 50 mM. These results suggest that the electrical conductivity of the salt solution, which reflects the solution osmotic potential, plays a significant role in preventing the splitting phenomenon, rather than the specific effect of Ca2+ ions, which prevented fruit tissue cracking. Thus, in order to prevent the stem-base splitting in cut Zantedeschia flowers, it is recommended to pulse the stems for 24 h with any salt solution at a concentration that yields an electrical conductivity of at least 5600 µS cm‑1. The salt solutions should be prepared in tap water in the presence of chlorine (50 µg L‑1), to avoid pathogen development during pulsing. The results suggest a simple, very effective, and low cost treatment to prevent the stem-base splitting also in other geophyte cut flowers that suffer from this problem.
Salim, S., Philosoph-Hadas, S. and Meir, S. (2019). Prevention of stem-base splitting in cut Zantedeschia aethiopica flowers by pulsing with salt solutions. Acta Hortic. 1263, 375-382
salts, electrical conductivity, tap water, geophyte cut flowers, sucrose, preservatives, osmotic potential