Relationship among floral scent intensity, ethylene sensitivity, and longevity of carnation flowers

Floral fragrance is a vital factor for the marketability of ornamental flowers, and it may also influence flower longevity. Despite several studies on the relationship between floral fragrance and flower longevity, a scientific consensus about this relationship has not been established to date. To investigate the influence of floral scent level on ethylene sensitivity and flower longevity, we determined the relationship between the mRNA levels of ethylene biosynthesis genes and senescence characteristics of low- and high-scent carnation cultivars after ethylene treatment. In this study, we demonstrated that high floral scent is related to increased sensitivity to ethylene as a consequence of transcriptional accumulation of the ethylene biosynthesis genes DcACS1 and DcACO1 in carnations. Flower senescence symptoms responsible for vase life termination following ethylene exposure differed depending on the floral scent level; while low-scent flowers terminated their vase life due to brown edges and wilting, high-scent flowers terminated their vase life earlier due to petal inrolling, which resulted from their rapid tissue response to ethylene. The results revealed that the longevity of carnation flowers is strongly negatively correlated with floral scent level and ethylene sensitivity and that the initial transcript level of DcACO1 contributed the most to the vase life of high-scent flowers. This result suggested that floral scent intensity is closely related to ethylene sensitivity in carnation flowers. High floral scent is correlated with a rapid tissue response to exogenous ethylene and consequently shortens the vase life of carnation flowers.