|Lee, Jong Suk|
Submitted to: Acta Horticulturae
Publication Type: Proceedings
Publication Acceptance Date: 2/2/2011
Publication Date: 7/8/2011
Citation: Lee, J., Roh, M.S. 2011. Carbohydrate changes during flower senescence of the Easter Lily (Lilium Longiflorum Thunb.). Acta Horticulturae. 900:295-300. Interpretive Summary: The longevity of cut flowers is generally determined by the visual symptoms of wilting of petals. Sugars, such as sucrose, glucoses and fructose, were the main constituents of petals and limitations of the reducing sugars may induce the onset of senescence. Although there is little evidence of breakdown of large cell wall polysaccharides, loss of galactose appears to be a common feature during the senescence of cut flower petals. The criteria to judge the post-harvest longevity of cut flowers are considered generally subjective and physical or chemical parameters must be developed to evaluate longevity objectively. Changes in cell wall components and soluble sugars in association with various floral organs during flower senescence in the Easter lily have not been investigated. In the Easter lily, Lilium longiflorum, it is possible that a rapid decrease in glucose and fructose could arrest anther development or the maturation of pollen, which triggers ethylene evolution from the anther. Further studies are needed to investigate the level of free galactose in the tepal as that may relate to the evolution of ethylene.
Technical Abstract: This research was initiated to examine changes in ethanol soluble carbohydrates and cell wall neutral sugar composition in various floral organs of cut Lilium longiflorum Thunb. (Easter lily) flowers. Fresh weight of anthers decreased sharply, reaching a minimum level 3 days post-anthesis (DPA). Tepals began to lose their firmness 6 DPA, and flowers were considered senesced 11 DPA. The level of soluble sucrose from anthers was the highest 2 to 3 DPA. Conversely, the level of glucose and fructose reached their lowest levels, thus limiting the available carbon sources in anthers after anthesis. Arabinosyl and galactosyl residues were only detected in polysaccharides from exudates produced at the latter stages of flower development. The xylosyl, galactosyl, rhamnosyl, non-cellulosic glucosyl, mannosyl, and arabinosyl contents of cell wall materials decreased by 50% 3 DPA. Galactose and xylose were the major cell wall neutral sugar components, and remained the highest compared to other cell wall sugar residues during the entire period of flower bud senescence. It is possible that a rapid decrease in glucose and fructose could arrest anther development or the maturation of pollen and trigger tepal senescence.