Flower Stem Blockage in Cut Orchid, Lotus, and Canna

Abstract

Important problems of cut flowers are short vase life and rapid senescence possibly caused by water deficit, a consequence of stem end blockage which has various nature of occurrence. The aim of this study was to investigate the stem end blockage in Dendrobium ‘Khao Sanan’ orchid, lotus (Nelumbo nucifera Gaertn., cv. Saddhabutra) and canna. The result showed that water uptake of these flowers which their stems were cut in the air or cut under water or cut and left in the air for 1 hour before holding in distilled water was not significantly different among treatments.  This result indicated that air embolism may not be the cause of vascular occlusion in these flowers.  The rate of water uptake of orchid flowers held in 8-hydroxyquinoline sulfate (HQS) solution was higher than those in distilled water while the rate of water uptake and vase life of lotus and canna flowers were not different from those held in distilled water. Holding these flowers in different solutions containing phenolic compound synthesis inhibitors: S-carvone (0.032-0.636 mM), tropolone (0.25 and 0.5 mM), 4-hexylresorcinol (4-400 µM) and amitol (1, 2, 3, 5 and 10 mM) showed that water uptake and vase life were not different from those held in distilled water but the vase life of orchid flowers held in 4-hexylresorcinol and amitol were longer than those held in distilled water. It is concluded that microorganisms and phenolic compounds may be the cause of stem end blockage in orchid flowers but not in lotus and canna flowers.