Cold storage and flower keeping quality of cut tuberose (Polianthes tuberosa L.)

The vase life and floret opening of cut tuberose inflorescences were signif icantly decreased by cold storage. The ideal storage temperature was found to be 0 degreesC for short durations because even storage at 2 degreesC for only 3d significantly decreased floret opening and the vase life of stored inflorescences. There was no significant difference between "wet" storage in a preservative solution (250 ppm 8-hydroxyquinoline citrate, 2% sucrose) and "dry" storage (spikes wrapped in polythene film to reduce water loss). Pre-storage pulsing with a 20% sucrose solution (containing HQC) significa ntly improved the vase life and opening of cold-stored spikes. The vase lif e and floret opening of spikes treated in this way were equal, after 6 d of storage at 2 degreesC, to those of fresh cut inflorescences. The end of th e vase life of cut tuberose spikes coincided with the time taken to return to their initial fresh weight. Cold storage resulted in a pronounced increa se in ethylene production by the florets, particularly by immature buds. Et hylene treatment of fresh cut tuberose spikes reduced floret opening, but e thylene induced by cold storage did not appear to be the cause of reduced f loret opening. Pretreatment of spikes with STS eliminated the effects of ex ogenous ethylene on fresh spikes, but had no effect on the reduced vase lif e of cold-stored flowers and substantially increased ethylene production by their florets. Ethylene production by florets of sucrose-pulsed spikes was similar to that of the controls. It appears that the shortened vase life o f cold-stored tuberose is not due to the induction of ethylene biosynthesis .