Effects of ethylene, pollination, and ethylene inhibitor treatments on flower senescence of gentians

Abstract

Flower senescence of the potted gentian (Gentiana scabra) 'Shinbisei' was investigated in relation to ethylene sensitivity and production. 'Shinbisei' flowers were used for all experiments except for those with inflorescences. Exposure to ethylene at 0.5μLL-1 or higher concentrations for 24h markedly accelerated flower senescence, indicating that G. scabra flowers are highly sensitive to ethylene. Treatment with 0.2 or 0.5mM silver thiosulfate complex (STS) and 2μLL-1 1-methylcyclopropene (1-MCP), ethylene action inhibitors, and 50mM α-aminoisobutyric acid, an inhibitor of 1-aminocyclopropane-1-carboxylate (ACC) oxidase, did not delay flower senescence. However, treatment with 1mM l-α-(2-aminoethoxyvinyl) glycine, an inhibitor of ACC synthase, slightly delayed flower senescence. Pollination significantly accelerated petal senescence of G. scabra flowers. Ethylene production of petals, gynoecium, and stamens in unpollinated flowers slightly increased during senescence. Pollination significantly increased ethylene production of petals, gynoecium and stamens 1 day after pollination. To clarify whether 1-MCP delays senescence of cut gentian inflorescences, cut G. scabra 'Yuki-hotaru', G. scabra×Gentiana triflora 'Aoi-kaze', and G. triflora 'Koharu' inflorescences with various stages of flowers, including buds with colored petals, were treated with 2μLL-1 1-MCP for 24h. 1-MCP treatment delayed flower wilting of cut inflorescences of 'Aoi-kaze' and 'Yuki-hotaru' more than that of 'Koharu', suggesting that there is species variation in the effect of 1-MCP in delaying flower senescence of cut gentian inflorescences. © 2011 Elsevier B.V..