The Effect of the Long-Term Cold Storage and Preservatives on Senescence of Cut Herbaceous Peony Flowers

Recently peonies have become very popular cut flowers. As peony flowering period is short, long term cold storage could assure its prolonged supply and make long distance transport feasible. The effect of dry cold storage, of 8-hydroxyquinoline and nanosilver preservatives on the peony keeping qualities were tested on the most popular cultivar ‘Sarah Bernhardt’. The 12 week storage (0–1 °C) shortened flower longevity by 20%, to 8 days and no vascular blockages in the shoots were observed. However, the presence of callose, not considered as a blocking factor, was evident. The sucrose-containing preservatives with either 8-hydroxyquinoline or nanosilver did not extend the flower longevity but they increased flower diameters in both fresh and stored material. Generally, the soluble total and reducing sugars increased in senescing flowers in both non-stored and stored flowers, and they were lower after storage. The free proline increased ca. 20-times during cold storage and at the end of the vase life it remained generally higher in the stored than in fresh flowers. The level of hydrogen peroxide dropped after 12 weeks storage and its contents at the end of the vase life differed depending on the holding solution. Generally it was lower after storage. Storage increased the catalase activity which remained on higher levels in stored flowers from all holding solutions as compared to freshly cut flowers. A five-fold reduction in the peroxidase activity occurred during storage but its activities at the end of the vase life were similar in stored and non-stored flowers. The effects of nanosilver and 8-hydroxyquinoline were similar.