Carbon Balance and Flower Quality of Bud-Cut Carnations during Flower Bud Opening under Elevated Photosynthetic Photon Flux Density

Carbon balance and flower quality of post-harvest flower bud opening (FBO) were studied in cut shoots of the standard red carnation ‘Francesco’. For each FBO treatment, six ‘tight bud’ - cut carnations were placed in a ventilated transparent cylindrical container, separated into two compartments (flower heads, 25±1°C, 85±5% RH and leaves/stems, 23±1°C, 95±5% RH) by a transparent acrylic plate under continuous light with a PPFD of 30 (P30), 90 (P90) or 150 (P150) μmol m-2 s-1 with the cut ends in flower opening solution (25 mg L-1 AgNO3, 200mg L-1 8-hydroxyquinoline citrate, and 30g L-1 sucrose) . The time required for FBO was reduced for higher PPFD for Experiment A (8.0 d in P30, 7.0 d in P90, and 6.0 d in P150, respectively) and Experiment B (6.0 d in P30, 5.0 d in P90, and 5.0 d in P150, respectively) . The mean flower quality scores of opened carnations after FBO closely correlated with total carbon uptake (TCU) with correlation coefficients of 0.94 and 0.98 during 10-d flower quality evaluation for Experiments A and B. Carbon from net CO2 exchange per stem (CNCE) and carbon from gross photosynthesis (CGP) of leaves/stems in P150 was greater than those in P90 and P30.