Shortage of soluble carbohydrates is largely responsible for short vase life of cut 'Sonia' rose flowers

Abstract

To clarify to what extent vascular occlusion or shortage of soluble carbohydrate shortens vase life of cut 'Sonia' roses (Rosa hybrida L.), cut flowers were continuously treated with 200 mg·liter-1 8-hydroxyquinoline sulphate (HQS group), 20 g·liter-1 sucrose (Suc group) or 20 g·liter-1 sucrose plus 200 mg·liter-1 HQS (Suc + HQS group), whereas control flowers were kept in water. All cut flowers were kept at 23°C, 70% RH and 12 hr photoperiod, with 10 μmol·m-2·s-1 irradiance. Although all treatments extended the vase life, sucrose was more effective than HQS. Treatment with sucrose promoted unfolding of petals, suppressed the decrease in fresh weight of cut flowers, and inhibited the occurrence of blueing more than did HQS. Water conductivity of stem segments in the control and Suc groups decreased rapidly after harvest, but that in the HQS and Suc + HQS groups was maintained near the initial level for seven days. The number of bacteria in the stem segments increased in the control and Suc groups, but this increase was suppressed by HQS. Glucose, fructose and sucrose concentrations in petals in the Suc and Suc + HQS groups were much higher than those in the control or HQS groups. These results show that decrease in the soluble carbohydrate concentration in petals was more important than vascular occlusion in determining the vase life of cut 'Sonia' roses under our experimental conditions.