Effect of aminooxyacetic acid and sugars on the vase life of Dendrobium flowers

We investigated the effect of sugars and aminooxyacetic acid (AOA) on Dendrobium `Jew Yuay Tew¿ inflorescences bearing open flowers and flower buds. Glucose or sucrose in the vase water had no effect on vase life. AOA alone also did not improve vase life, but AOA together with sugars considerably increased it. The treatment suppressed bud drop, promoted bud opening, and delayed the time to senescence of open flowers. Its effect was counteracted by raising solution pH (which was 3.2) to 4.2 or higher. Bacterial counts in the vase solution were low at pH 3.2, but increased when the pH was raised. The pH of 0.5 mM AOA alone was initially about 3.0, but started to increase by day 8 of vase life and had reached pH 5 by day 12. When 4% glucose was added to this solution, the pH remained around 3 until day 20 of vase life. The combination of 0.5 mM AOA and glucose thus allows continuous uptake of water and dissolved sugars by the flower. It is concluded that the vase life of Dendrobium `Jew Yuay Tew¿ flowers is limited by adverse water relations and can be improved by sugars if water uptake is maintained