Influence of 8-Hydroxy Quinoline (8-HQ) and sucrose pulsing on membrane stability and postharvest quality of gladiolus cut spikes

The role of antimicrobial agent (8-HQ) and sucrose in the form of pulsing treatment on lipid peroxidation, membrane stability and postharvest keeping quality of gladiolus cut spikes was investigated, 8-HQ pulse treatment before the Eucrose treatment eliminated the microbial growth and improved the uptake of sucrose pulse treatment. The double pulsing treatment, comprising of 8-HQ (300 ppm) for a duration of one hour, followed by sucrose (20%) for a duration of 12 hour (double pulsing), revealed significantly enhanced water uptake and per cent gain in fresh weight as compared to control and single (sucrose) pulsed spikes. The double pulsed cut spikes exhibited lower lipid peroxidation and lipoxygenase (LOX) activity, which retained the ratio of poly unsaturated fatty acids of the lipid bilayer of the membrane resulting into its well maintained flexibility and selective permeability and thus, diminished the per cent of ion leakage. Superoxide dismutase (SOD) and Glutathione Reductase (GR) activities were also higher in the petals of the double pulsed cut spikes. All these factors contributed towards better membrane stability and delayed petal senescence and significantly extended the keeping of gladiolus cut spikes. Thus, the double pulse treatment improved the membrane stability and keeping quality of gladiolus flowers accompanied with enhanced per cent bud opening (93.6%) and floret width as compared to single sucrose pulse and control.