Floral preservatives are widely recommended for cut stems and are extensively used in floral arrangements by wholesalers, retailers, and consumers for extending longevity and maintaining quality (Ahmad et al., 2013b; Çelikel and Reid, 2002; Nowak and Rudnicki, 1990). They maintain water uptake by acidifying solutions and controlling microbial growth (McDaniel, 1996) and provide carbohydrates necessary to carry on metabolic activities after harvest (Meyer, 2010). They can improve color development of petals, encourage flower opening, and increase flower head size (Nowak and Rudnicki, 1990).
Several manufacturing companies produce different types and brands of floral preservatives, including hydrators and holding or vase solutions. Hydrators are used immediately after harvest or dry storage to improve water uptake by the stems as these contain acidifying agent without sugars. Holding/vase solutions contain sugars along with acidifiers and biocides, which provide food for maintaining metabolic processes and continued flower opening during vase life.
Among acidifiers, citric acid is the most common compound and is used to lower the pH of the preservative solutions and control microbial proliferation. Citric acid has been found effective for cut roses [Rosa ×hybrida (Jowkar et al., 2012)], gladiolus [Gladiolus hybrids (Tiwari et al., 2010)], carnations [Dianthus caryophyllus (Kazemi et al., 2012)], tuberoses [Polianthes tuberosa (Jowkar and Salehi, 2006)], and lisianthus (Kiamohammadi and Hashemaabadi, 2011). Citric acid lowers the pH of cell sap and prevents the blockage of xylem vessels, thereby improving water uptake and extending longevity. It promotes floral opening and maintains postharvest quality of cut tuberose spikes (Jowkar and Salehi, 2006).
Another compound used extensively to lower solution pH and control detrimental microbes in preservative solutions is aluminum sulfate. It is extensively used as a biocide for cut roses (De Stigter, 1981), lisianthus (Liao et al., 2001), and many other cut flower species. It has also been reported to improve keeping quality and vase life of cut roses (Ichimura et al., 2006) by stabilizing petal anthocyanin contents and lowering pH.
Sugars are the integral component of flower foods, providing essential carbohydrates to the cut stems and continuing metabolic processes necessary for extension of vase life. However, sugars must be used along with antimicrobial compounds to prevent microbial buildup in the solutions (van Doorn, 1997). Among these biocides, silver compounds such as silver nitrate and silver thiosulfate, chlorine compounds such as sodium hypochlorite and sodium dichloroisocyanurate, and several other compounds such as cobalt chloride, 8-hydroxyquinoline citrate or sulfate, quaternary ammonium chloride, or isothiazolinone are used to prevent microbial proliferation in vase solutions. Because of environmental hazards associated with silver compounds and 8-hydroxyquinoline citrate or sulfate and only short-term effectiveness of chlorine compounds, quaternary ammonium chloride and isothiazolinone can be used for handling cut flowers. Quaternary ammonium chloride disinfectant is stable, safe, and effective in controlling germs in vase solutions, particularly when freshly prepared solution is used. Isothiazolinone is another safe, effective, broad-spectrum, and globally approved preservative compound, which can also be used as a biocide in floral preservative solutions (Ichimura et al., 2006). However, limited information is available on effectiveness of these compounds for cut flower longevity.
Several other compounds have been used by the industry as biocides, acidifiers, or both in various homemade floral preservatives. Some of these include lemon/lime soda, lemon juice, vinegar, household bleach, aspirin tablets (Greer and Einert, 1994), pennies, or essential oils of several plant species (Fariman and Tehranifar, 2011; Samiee et al., 2013). However, limited information is available on their effectiveness on cut flowers postharvest longevity and quality. Commercial preservatives are well researched and effective, but not readily available in many parts of the world. In addition, several folk recipes also are being used by the industry and consumers, but limited scientific information is available about their effects on the longevity and quality of cut stems. Therefore, the present studies were conducted to determine the effect of different homemade floral preservatives on four popular specialty cut species. The specific objectives of the studies were to 1) develop readily available, environmentally safe, and low-cost floral preservative(s) for growers, florists, and consumers; and 2) evaluate the effects of different ingredients of folk floral recipes being used by the industry. It was hypothesized that the recipes would extend the vase life of tested species as much as commercial preservative solutions.
Ahmad, I., Dole, J.M., Carlson, A.S. & Blazich, F.A. 2013a Water quality affects vase life of cut callas, hydrangeas and snapdragons Sci. Hort. 153 26 33
Ahmad, I., Dole, J.M., Saleem, M., Khan, M.A., Akram, A. & Khan, A.S. 2013b Preservatives and packaging material have an impact on the post-harvest longevity of cut Rosa hybrida L. ‘Kardinal’ flowers J. Hort. Sci. Biotechnol. 88 251 256
De Stigter, H.C.M. 1981 Effects of glucose with 8-hydroxyquinoline sulfate or aluminum sulfate on the water balance of cut ‘Sonia’ roses Zeitschrift fur Pflanzenphysiologie 101 95 105
Elhindi, K.M. 2012 Effects of postharvest pretreatments and preservative solutions on vase life longevity and flower quality of sweet pea (Lathyrus odoratus L.) Photosynthetica 50 371 379
Fariman, Z.K. & Tehranifar, A. 2011 Effect of essential oils, ethanol and methanol to extend the vase-life of carnation (Dianthus caryophyllus L.) flowers J. Biol. Environ. Sci. 5 91 94
Gast, K.L.B. 2000 Water quality: Why it is so important for florists. Kansas State Univ. Ext. Publ. MF-2436
Ichimura, K., Taguchi, M. & Norikoshi, R. 2006 Extension of the vase life in cut roses by treatment with glucose, isothiazolinonic germicide, citric acid and aluminum sulphate solution Jpn. Agr. Res. Qrtly. 40 263 269
Jowkar, M.M. 2005 Effects of different compounds on the microbial population of cut ‘Shiraz narcissus’ vase solution Acta Hort. 682 1705 1708
Jowkar, M.M. & Salehi, H. 2006 The effects of different preservative solutions on the vase life of cut tuberose (Polianthes tuberosa L.) cv. Goldorosht-e-mahallat J. Sci. Technol. Agr. Natural Resources 10 299 309
Jowkar, M.M., Kafi, M., Khalighi, A. & Hasanzadeh, N. 2012 Reconsideration in using citric acid as vase solution preservative for cut rose flowers Current Res. J. Biol. Sci. 4 427 436
Kazemi, M., Hadavi, E. & Hekmati, J. 2012 Effect of salicylic acid, malic acid, citric acid and sucrose on antioxidant activity, membrane stability and ACC-oxidase activity in relation to vase life of carnation cut flowers J. Plant Sci. 7 78 84
Kiamohammadi, M. & Hashemaabadi, D. 2011 The effects of different floral preservative solutions on vase life of lisianthus cut flowers J. Ornamental Hort. Plants 1 115 122
Liao, L.J., Lin, Y.H., Huang, K.L. & Chen, W.S. 2001 Vase life of Eustoma grandiflorum as affected by aluminum sulfate Bot. Bull. Acad. Sin. 42 35 38
McDaniel, G.L. 1996 Floral design and arrangement. 3rd ed. Prentice Hall. Upper Saddle River, NJ
Meyer, M.H. 2010 Keeping cut flowers and flowering plants. 16 Feb. 2010. <http://www.extension.umn.edu/distribution/horticulture/dg7355.html>
Nowak, J. & Rudnicki, R.M. 1990 Postharvest handling and storage of cut flowers, florist greens and potted plants. Timber Press, Portland, OR
Samiee, M., Zarchini, M., Vand, S.H. & Hashemabadi, D. 2013 Improvement of vase life, protein content and postharvest quality of Dendranthema grandiflorum L. cv. White by Artemisia oil Ann. Biol. Res. 4 127 129
Tiwari, A.K., Bhuja, B.D. & Mishra, S.K. 2010 Impact of certain chemicals on vase life of different cultivars of china aster and gladioli Indian J. Hort. 67 255 259
van Doorn, W.G., Zagory, D., de Witte, Y. & Harkema, H. 1991 Effects of vase-water bacteria on the senescence of cut carnation flowers Postharvest Biol. Technol. 1 161 168