Phalaenopsis spp. have become popular commodities in the world; their long-lasting flowers are an attractive characteristic for consumers. The postharvest life of potted Phalaenopsis can extend to more than 3 months. Like most orchids, however, the Phalaenopsis flower is susceptible to C2H4 stress (Hew and Yong, 2004). Exposure of Phalaenopsis Snow Mist ‘Large Sepal’ flowers to 0.09 μL·L−1 ethylene for 66 h resulted in wilting (Lee and Lin, 1992). Ethylene can come from many sources such as emissions from internal combustion engines, pollutants released into the atmosphere, normal emissions from plant organs and from fungal metabolism, etc. (Martínez-Romero et al., 2007). Damaging concentrations of ethylene commonly occur during postharvest, transportation, and marketing and can reduce product quality.
1-Methylcyclopropene is an ethylene inhibitor that is widely used to maintain the freshness of ornamental plants and flowers and delay the ripening of fruits. 1-Methylcyclopropene works by tightly binding to ethylene receptors in plants, thus competing with ethylene for available binding sites. The affinity of 1-MCP for ethylene receptors is 10 times greater than that of ethylene. Therefore, once ethylene receptors are fully occupied by 1-MCP molecules, both endogenous and exogenous ethylene responses are inhibited (Serek et al., 2006).
The residual protection by 1-MCP against ethylene-induced effects is limited (Sisler and Serek, 1999). Cymbidium flowers subjected to 1-MCP pretreatment resisted ethylene stress for up to 2 weeks but wilted when ethylene was applied at Week 3 (Philosoph-Hadas et al., 2005). When ethylene receptors in plant tissues are fully blocked by 1-MCP, 7 to 12 d are required for 50% receptor regeneration (half diffusion time; Sisler and Serek, 1999). After that, the inhibitory efficacy on the ethylene response gradually decreases. Based on the abscission percentage after 2 h of ethylene exposure, the half-lives of 1-MCP activities in Pelargonium peltatum flowers were ≈2, 3, and 6 d after 1-MCP treatment at 25, 20.7, and 12 °C, respectively (Cameron and Reid, 2001), demonstrating that the residual effect of 1-MCP is affected by temperature.
Multiple applications of 1-MCP can be a strategy to prolong protection times. For example, apple fruit became soft 40 d after 1-MCP treatment, but multiple 1-MCP applications delayed the occurrence of ripening (Mir et al., 2001). A single application of 1-MCP on green-mature tomatoes delayed fruit coloration by 6 d, but a second application applied at 10 d after the first treatment delayed coloration for another 8 to 10 d (Mir et al., 2004). 1-Methylcyclopropene was reported to be efficacious in retarding ethylene-induced flower wilting in Phalaenopsis (Lin et al., 2003; Segliea et al., 2010; Sun et al., 2009). Pretreating Phalaenopsis amabilis with 0.8 μL·L−1 1-MCP for 4 h fully inhibited the wilting of flowers and flower buds (Lin et al., 2003). The residual effect of 1-MCP in Phalaenopsis is of great interest because it has emerged as an economically important potted plant. However, such information is not available in the literature.
In the current study, we determined the residual effect of 1-MCP in preventing ethylene damage to flowers and buds of P. amabilis. The effects of post-1-MCP-treatment temperatures and multiple 1-MCP applications on the residual efficacy were also investigated.
Cameron, A.C. & Reid, M.S. 2001 1-MCP blocks ethylene-induced petal abscission of Pelargonium peltatum but the effect is transient Postharvest Biol. Technol. 22 169 177
Hew, C.S. & Yong, J.W.H. 2004 The physiology of tropical orchids in relation to the industry. 2nd Ed. World Scientific Publishing Co. Pte. Ltd., Singapore
Hoeberichts, F.A., van der Plas, L.H.W. & Woltering, E.J. 2002 Ethylene perception is required for the expression of tomato ripening-related genes and associated physiological changes even at advanced stages of ripening Postharvest Biol. Technol. 26 125 133
Lin, H.H., Lee, N. & Chang, T.H. 2003 Effects of ethylene and 1-MCP pretreatment on flower wilting of potted Phalaenopsis amabilis var. formosa Shimadzu J. Chinese Soc. Hort. Sci. 49 199 210 [in Chinese with English abstract]
Lin, W.L. 2006 Effects of ethylene and 1-methylcyclopropene on flower longevity in Phalaenopsis amabilis. MS thesis, Natl. Taiwan Univ. Taipei, Taiwan [in Chinese with English abstract]
Martínez-Romero, D., Bailén, G., Serrano, M., Guillén, F., Valverde, J.M., Castillo, P.Z.S. & Valero, D. 2007 Tools to maintain postharvest fruit and vegetable quality through the inhibition of ethylene action: A review Crit. Rev. Food Sci. Nutr. 47 543 560
Mir, N.A., Curell, E., Khan, N., Whitaker, M. & Beaudry, R.M. 2001 Harvest maturity, storage temperature, and 1-MCP application frequency alter firmness retention and chlorophyll fluorescence of ‘Redchief Delicious’ apples J. Amer. Soc. Hort. Sci. 126 618 624
Philosoph-Hadas, S., Golan, O., Rosenberger, I., Salim, S., Kochanek, B. & Meir, S. 2005 Efficiency of 1-MCP in neutralizing ethylene effects in cut flowers and potted plants following simultaneous or sequential application Acta Hort. 669 321 328
Reid, M. & Çelikel, F.G. 2009 Use of 1-methylcyclopropene in ornamentals: Carnations as a model system for understanding mode of action HortScience 43 95 98
Segliea, L., Sisler, E.C., Mibusa, H. & Serek, M. 2010 Use of a non-volatile 1-MCP formulation, N,N-dipropyl (1-cyclopropenylmethyl) amine, for improvement of postharvest quality of ornamental crops Postharvest Biol. Technol. 56 117 122
Serek, M., Woltering, E.J., Sisler, E.C., Frello, S. & Sriskandarajah, S. 2006 Controlling ethylene responses in flowers at the receptor level Biotechnol. Adv. 24 368 381
Sun, Y., Christensen, B., Liu, F., Wang, H. & Müller, R. 2009 Effect of ethylene and 1-MCP (1-methylcyclopropene) on bud and flower drop in mini Phalaenopsis cultivars Plant Growth Regulat. 59 83 91