Improvement of postharvest vase life and flower bud opening in Polianthes tuberosa using gibberellic acid and sucrose

Pulsing with gibberellic acid followed by continuous sucrose treatment enha nced flower longevity and flower bud opening in cut Polianthes tuberosa L. cv. Double. Pulsing with gibberellic acid at 10 or 20 mg/L plus 8-hydroxyqu inoline sulfate (200 mg/L) for 24 h followed by continuous sucrose treatmen ts (4 or 8%) plus 8-hydroxyquinoline sulfate extended the vase life and sig nificantly promoted flower bud opening as compared with the 8- hydroxyquino line sulfate controls. A pulse with a higher concentration of gibberellic a cid (50 mg/L) followed by sucrose solutions did not increase vase life or e nhance flower bud opening greater than those pulsed with gibberellic acid a t 10 or 20 mg/L followed by 8- hydroxyquinoline sulfate. A gibberellic acid (10, 20 or 50 mg/L) pulse followed by 8- hydroxyquinoline sulfate holding solution had little effect on longevity and flower bud opening in compariso n to 8- hydroxyquinoline sulfate controls. Similarly, continuous sucrose tr eatment at 4 or 8% without a gibberellic acid-pulsed treatment also showed little effect on vase life and flower bud opening. Cut P. tuberosa treated with a gibberellic acid pulse followed by 8- hydroxyquinoline sulfate produ ced more ethylene than those treated with 8- hydroxyquinoline sulfate alone . Ethylene production from flowers pulsed with gibberellic acid followed by sucrose was low when compared with controls or those pulsed with gibberell ic acid alone. Cut stems continuously placed in solutions containing sucros e produced less ethylene than those without sucrose. It is suggested that a gibberellic acid pulse at 10 mg/L followed by continuous sucrose treatment at 4% be recommended to growers for extending the vase life and enhancing flower bud opening in cut P. tuberosa.