| Lily(Lilium spp.) is a perennial herbaceous flower, and it belongs to the Liliaceae, Lilium. It is popular among the people of the world because of its huge and beautiful flowers, rich colors and fragrant smell, as one of the world’s four major cut flowers. However, fresh cut flowers are a living organ that is detached from the parent plant, it is a very concerned problem of flower operators and consumers that how to make fresh cut flowers as much as possible to maintain fresh, aiming to extend the viewing period. In addition, for the majority of lily cut flower, leaf yellowing is a serious problem, which can limit the overall vase life of flowers. Therefore, increasing the ornamental value of the leaves is also an important part of the preservation of cut flowers.In this study, Lily Casa Blanca was used as test material to research the effects of cold storage on lily flowers and reduce its leaf yellowing by the method of hot water treatment, and determine the related physiological indexes of leaves after treatment. Moreover, the optimum concentration of sucrose was screened as a vase solution, and evaluate it effect on mechanism in lily cut flower opening and senescence process.The main results are summarized as follows:(1) The lily cut flowers storage at 4℃ in water were speeded up to open, and the longer the cold storage effect is more obvious. The time to tepal senescence in water aslo decrease with the time of storage. The time to tepal abscission was about 1 day longer than the time to tepal senescence. Compared to cold storage in water, dry storage at 4 ℃ further speeded up the bud opening and also further speeded up the tepal senescence and abscission. Dry storage also caused more buds that desiccated and open not completely. Sucrose treatment(100g/L) weakened the negative impact of dry cold.(2) A series of hot water treatments(45~55℃, 2.5 or 5 min) were carried out to the leaves of lily cut flowers. The results showed that higher temperatures and longer processing time lead to thermal damage, but treatments of 50℃ for 5 min were found to be optimal for minimising leaf yellowing with trace levels of heat damage for both non-stored and stored stems. The leaf yellowing can be delayed 3~4 days occurred, and the time to unacceptable degree of yellowing were 12 days. Chlorophyll fluorescence yield(Fv/Fm) of leaves of control decreased over time,and the phenomenon is more obvious in the basal leaves than the upper leaves. Although both optimal hot water treatments resulted in an initial reduction in yield, there was a recovery over time resulting in a yield that by 12 d, was as high or significantly higher than control leaves(particularly for the lower leaves). All treatments showed a reduction in chlorophyll content(total, chlorophyll a and chlorophyll b), but control leaves had significantly lower after 7 d.(3) A certain concentration of sucrose as a lily cut can be used to extend the vase life, increasethe diameter of bud, promote the blossom, and improve the ornamental value of leaves in different degrees. Changes of the measured indexes showed that 5g/L was the optimal concentration for sucrose as the vase solution.(4) Endogenous glucose content increased during the flowers opening and decreased during senescence in all floral organs, however, the sucrose content in outer and inner tepals and stamens increased during senescence. The addition of sucrose in the vase solution accelerated the opening of the flowers, and delayed the senescence, but did not affect the petals abscission. The content of cytokinin and auxin in the pistil increased, the content of endogenous, endogenous, salicylic acid and salicylic acid were increased in the stamens, however, abscisic acid content in the outer tepals decreased. It can be concluded that, among other factors, the addition of sucrose in the vase solution may affect the opening and senescence of flowers by altering the hormonal balance of some floral tissues. |
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