Effects of Preservatives Applied at Different Flowering Stages on Cut Flower Senescence of Oncidium Gower Ramsey

Key words: 
• Oncidium Gower Ramsey /
• flower senescence /
• preservative /
• STS /
• 1-MCP /
• ethephon /
• ethylene pro duction /
• ACC content

Abstract: Oncidium flowers（ Oncidium Gower Ramsey） at different flowering stages were treated with ethylene agents such as silver thiosulfate（ STS） and 1-methylcyclopropene（ 1-MCP）,and ethylene releaser ethephon to observe the effects of the ethylene agents used as preservatives on cut flowers. The results show that the aging process of Oncidium flowers could be obviously shortened by ethephon application after the half-opened stage.The STS treatment could prolong the prior-to-full-opening stage and the full-opened stage of flowers. The 1-MCP treatment could delay the senescing progression of flowers at the initial stage of senescence and the senescence stage. The ethylene production and 1-aminocyclopropane-1-carboxylic acid（ ACC） content of the flower parts at different flowering stages were determined. The results showed that ACC contents of the gynandria and sepals of the cut flowers were steady during the bud-burst stage and the half-opened stage,but rose after the half-opened stage,and that ethylene production increased after the prior-to-full-opening stage. ACC contents of petals increased slowly after the prior-to-full-opening stage and peaked at the initial stage of senescence. The effectiveness of the preservatives appeared to be strongly affected by the initiation of endogenous ethylene biosynthesis in Oncidium cut flowers.