Flower longevity in ten cultivars of cut Ranunculus asiaticus L. as affected by ethylene and ethylene inhibitors

The role of ethylene on ranunculus cut flower senescence was investigated. Ten Ranunculus asiaticus cultivars (‘Pluto’, ‘Juny’, ‘Shangai’, ‘Auriga’, ‘Bianco2’, ‘Ken’, ‘Dido’, ‘Lulù’, ‘Saigon’ and ‘Green’) were treated with 2 mM silver thiosulfate (STS), 4 mM amino-oxyacetic acid (AOA), and 377 nL L–1 1-methylcyclopropene (1-MCP, Ethylbloc™) for 14 h and with 8 μL L–1 ethylene for both 14 and 72 h. Evaluation of postharvest performance was based on: visual check for symptoms of senescence alteration (VS), stem fresh weight (FW), petal colour, ethylene production, and leaf chlorophyll content. Results showed genotype differences for all parameters. Senescence was usually reached about 13 d after the beginning of the experiment. In untreated flowers, ‘Green’ was the longest-lived (16.2 d) and ‘Lulù’ the shortest-lived (11.1 d). Statistical analysis showed an interaction between cultivar and treatment. In general, AOA and STS treated flowers lasted more than the control. These molecules are inhibitors of ethylene biosynthesis or ethylene action respectively. However, they can also act as antibacterial agents. More in detail, AOA extended the longevity in four out of ten cultivars (‘Lulù’, ‘Pluto’, ‘Bianco2’ and ‘Green’) and STS in two (‘Pluto’ and ‘Bianco2’). Exogenous ethylene application did not negatively affect any of the investigated cultivars. Overall it can be concluded that the new ranunculus cultivars tested are ethylene insensitive. Therefore special precautions against exposure to ethylene are not needed.