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

Abstract

The vase life and floret opening of cut tuberose inflorescences were signifiantly decreased by cold storage. The ideal storage temperature was found to be 0˚C for short durations because even storage at 2˚C for only 3.d significantly decreased floret opening and the vase life of stored inflorescences. There was no signficant difference between “wet”storage in a preservative solution (250.ppm 8-hydroxyquinoline citrate, 2% sucrose) and “dry” storage (spikeswrapped in polythene film to reduce water loss). Pre-storage pulsing with a 20% sucrosesolution (containing HQC) significantly improved the vase life and opening of cold-stored spikes. The vase life and floret opening of spikes treated in this way were equal, after 6.d of storage at 2˚C, to those of fresh cut inflorescences. The end of the vase life of cut tuberosespikes coincided with the time taken to return to their initial fresh weight. Cold storage resulted in a pronounced increase in ethylene production by the florets, particularly by immature buds. Ethylene treatment of fresh cut tuberose spikes reduced floret opening, but ethylene induced by cold storage did not appear to be thecause of reduced floret opening.Pretreatment of spikes with STS eliminated the effects of exogenous ethylene on fresh spikes, but had no effect on the reduced vase life 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 of cold-stored tuberose is not due to the induction of ethylene biosynthesis.