Delaying Flower Opening of Cut Roses by cis-Propenylphosphonic Acid

Abstract

The effect of a pulse treatment with cis-propenylphosphonic acid (PPOH) on the opening of cut rose flowers (Rosa hybrida L.) was investigated. Treatments with a 5 or 10 mM PPOH solution for 20 hr delayed opening of cut 'Sonia' roses kept in vase water at 20°C. PPOH had no effect on the change of the flower weight. In this experiment, the cumulative water uptake of PPOH-treated flowers during the first 4 days decreased accompanied by a simultaneous decrease in total transpiration. Analysis of the similar experimental results obtained from June 1989 to July 1990 revealed a significant, positive correlation between the delaying effect of PPOH on the flower opening and PPOH uptake into the flowers (P < 0.01). In field experiments in which PPOH-treatment was carried out in a commercial planting grower, 5 or 10 mM PPOH treatment for 30 hr also delayed the flower opening of cut 'Carlred' roses. The delaying effect of PPOH was more evident when flowers were kept in vase water at 10°C than were kept at 20°C. The treatment was effective even with a 6-hr treatment. When the PPOH-treated flowers were held at 10°C for 2 days longer than the water-treated ones. the former were comparable to or superior with the latter in their opening rates and appearance when both lots were transferred to 20°C. Similar PPOH results were obtained with 'Bridal Pink', 'Aalsmeer Gold' and 'Marina'. The results indicate that PPOH pulse treatments: 1) can delay the opening of cut rose flowers, particularly when held at 10°C, and 2) may extend the shelf life of the flowers if refrigerated in the stockroom at a retail shop.