The Role of Soluble Sugars in Vase Solutions during the Vase Life of Eustoma grandiflorum

Abstract

The vase life of Eustoma cut flowers can be extended by adding sugars to the vase solution, but the exact role of sugars and how they are translocated in tissues are not clear. Thus, we observed the preserving effect of different sugars in vase solutions on Eustoma and compared sugar concentrations in vase solutions and in the flowers as well as stems and leaves of cut flowers in a solution containing 200 mg·L−1 8-hydroxyquinoline sulfate (8-HQS) with and without 20 g·L−1 sucrose during different flowering stages. Inclusion of glucose, fructose, or sucrose in the vase solution extended the vase life of cut flowers with no significant differences among sugar types. During flower opening, the concentration of added sucrose in the vase solution dropped, and the fresh weight (FW), glucose concentration, and sucrose concentration of flowers in sucrose solutions increased, whereas flowers in solutions without sucrose had lower FW and glucose concentrations. During flower senescence, sugar concentration in the vase solution did not change much, but the FW and sucrose concentrations in all flowers declined, although the FW of sucrose-treated flowers fell more slowly. For stems and leaves in the sucrose solution, sugar concentrations increased during the first 7 days with only glucose slightly declining during senescence, whereas the FW was maintained during the entire vase life. In contrast, FWs of those in the solution without sucrose gradually declined. In conclusion, sucrose in the vase solution promoted flower opening and maintained the water balance of Eustoma cut flowers. Glucose and fructose also extended the vase life, likely in similar ways.