EFFECTS OF LOW O2 ON CUT ROSE FLOWERS AT SUBOPTIMAL TEMPERATURE
There is no commercial application of modified atmosphere storage or packaging for cut flowers. The reason for that would be that the most decisive factor for keeping quality is a low temperature during storage and transport. In practice, however, this low temperature is not always realised. However it is worthwhile knowing potential quality benefits that may arise from the use of modified O 2 and/or CO 2 concentrations at sub-optimal temperatures. Experiments have been conducted on cut rose
... cted on cut rose flowers 'First Red' to study the effect on postharvest physiology of different O 2 partial pressures (0.5-21 kPa) during 5 days at 12 °C. During this period of transport simulation at different O 2 partial pressures, respiration rate and ethylene production of the flowers was measured. During subsequent flower opening during vase life, diameter and longevity of the flowers were recorded. Fresh weight and area of single petals were measured daily. Growth during vase life of the inner and outer petal surfaces was estimated. Oxygen uptake rate and ethylene production were logarithmically related to O 2 partial pressure. To lower oxygen uptake rate to less than 50% of that in air, a partial pressure of O 2 should be <2 kPa. However, in the O 2 range <2 kPa the R(espiratory) Q(uotient) indicated anaerobic respiration. Vase life was not significantly affected by O 2 concentrations during a 5 day storage period. Low O 2 partial pressures during storage resulted in poor flower opening afterwards. Petal growth was not inhibited by low O 2 -storage, but outer petals showed a greater increase in surface area and fresh weight after storage at 1 kPa O 2 than at higher O 2 partial pressures. Poor flower opening was the result of an increase in cell size at the upper region of the outer petal layer, which hampered outward reflex of the petals.