Characterisation of respiration, ethylene production, and carbohydrate contents during flower opening in Epidendrum ibaguense

The opening of flowers in Epidendrum ibaguense is characterised by continuous drops in respiration, ethylene production, and 1-aminocyclopropone-1-carboxylate (ACC) oxidase activity from the bud stage to fully open. Later, an increase in ethylene production and ACC oxidase activity occurred, suggesting autocatalytic production of ethylene, beginning at an early stage of senescence. Regardless of developmental stage, the main non-structural carbohydrates in flowers were non-reducing sugars [23.7% (w/w) fresh weight (FW)]. Starch accounted for 3.1% (w/w) FW and reducing sugars for 0.7% (w/w) FW No depletion in the level of any carbohydrate was observed throughout senescence. At the beginning of floral senescence, a sharp increase occurred in the activities of acid and alkaline invertases, suggesting a role for both enzymes in the cleavage of sucrose. However, no major changes in sucrose synthase activity were found during flower development.