Suppression of Malformed Petals in Cut Rose ‘Yves Piaget’ Flowers Caused by Pulse-Uptake Treatment of Methyl Jasmonate

Abstract

The most popular fragrant cut rose cultivar in Japan is ‘Yves Piaget’, but its petals often become malformed after harvest. These malformed flowers, referred to as “incurved flowers”, are characterized by petals curving toward the adaxial side which prevents normal flowering and significantly decreases the cut flower quality. It has been reported that jasmonic acid (JA) affects petal growth, and could suppress the emergence of incurved flowers. Therefore, in this study, we investigated the use of exogenous JA, methyl jasmonate (MeJA), applied to cut flowers of ‘Yves Piaget’ by 24 h pulse-uptake treatment. Results showed that 500 μM MeJA 24 h pulse-uptake treatment was effective at suppressing the number of incurved petals. Then, salicylic acid (SA), an antagonist of JA, was applied to see if the number of incurved petals increased. We compared three treatments: deionized water uptake treatment (control), 500 μM MeJA pulse-uptake treatment, and 500 μM SA continuous-uptake treatment. Vase life did not differ significantly between the three treatments, but the 500 μM MeJA pulse-uptake treatment produced a better-preserved flower shape due to only slight petal bluing and discoloration. In contrast, the control and 500 μM SA continuous-uptake treatments produced cut flowers with major petal wilting, bluing, and discoloration. The 500 μM MeJA pulse-uptake treatment tended to extend the number of days from flower bud to full bloom and decrease the number of incurved petals due to the continued high-water absorption. The commercial value of roses lies in the blooming process from bud until full bloom; the increased number of days from bud to full bloom after 500 μM MeJA pulse-uptake treatment improved the cut flower quality. In contrast, there was less water absorption and more incurved petals in the days after the 500 μM SA continuous-uptake treatment, indicating an antagonistic response to the 500 μM MeJA pulse-uptake treatment. In conclusion, treatment of ‘Yves Piaget’ cut flowers with 500 μM MeJA pulse-uptake could decrease the number of incurved petals and improve the cut flower quality.