Pulsing Treatments of Abscisic Acid and Sucrose for Improving Postharvest Quality of Cut Lily Flowers

Abstract

Abscisic acid (ABA), as a senescence phytohormone, has been proved to be related to flower petal senescence in rose (Mayak and Halevy, 1972; Kumar et al., 2008) and carnation (Nowak and Veen, 1982). Higher ABA concentrations were found in short–lived cultivars compared to long–lived rose cultivars (Halevy and Mayak, 1975). Exogenous application of ABA leads to enhancement of aging–related process in daffodil petals (Hunter et al., 2004). ABA, as one of the preservation agents, was also applied in the fresh–keeping of cut roses (Kohl and Rundle, 1972), Baccara roses (Pompodakis and Joyce, 2003; Pompodakis et al., 2004) and Eustoma flowers (Shimizu–Yumoto and Ichimura, 2009). ABA prolongs the vase life of cut roses with leaves, but shortens the vase life of leafless cut roses (Halevy et al., 1974). ABA can regulate water balance of cut flower through controlling stomata opening, increase the postharvest quality, and extend the vase life of cut flowers (Kohl and Rundle, 1972; Pompodakis and Joyce, 2003; Pompodakis et al., 2004). On the other hand it has been reported that ABA regulates water balance through ways other than stomata opening regulation (Borohov et al., 1976), the application of ABA did not affect the transpiration (Ichimura and Shimizu–Yumoto, 2007). ABA treatment can alleviate the sucrose–induced leaf chlorosis and improve the quality of cut flowers (Pompodakis and Joyce, 2003; Shimizu–Yumoto and Ichimura, 2009). Lilies are the world famous cut flowers with high ornamental value. Yang et al. (1996) indicated that ABA probably is the main factor affecting senescence of cut lilies, because morphology of cut flowers showed senescence symptoms following the peak of ABA, while ethylene can accelerate the aging process only to a certain extent. But Li et al. (2012) indicated that the addition of lower concentrations of ABA with sucrose and 8–hydroxyquinoline citrate (8–HQC) induced the increase of fresh weight, and partly alleviate the sucrose–induced leaf yellowing. Based on the above researches, the preservation mechanism of ABA in cut lilies is still not clear. Lilium ‘Sorbonne’ (Oriental hybrid group) was used as an experimental material in this study to observe the preservation effect of ABA, and to confirm further the preservation mechanism of ABA by determining the physiological indices and ethylene release of cut ‘Sorbonnes’ petals during postharvest.