P. nobilis cvs. Passion and Purity plants were grown under field
conditions in 14 cm pots between December (Summer) and June
(Winter) at The University of Queensland, Gatton Campus (latitude
27◦32 S, longitude 152◦20 E) or at Queensland Department
of Agriculture, Fisheries and Forestry, Hamilton (latitude 27◦44 S,
longitude 153◦07 E). Stems of the desired maturity with terminal
inflorescences and 45–70 cm length were harvested, stood in
distilled water, recut under water and immediately taken to the
laboratory. Harvest was consistently in the morning to ensure no
potential temporal circadian rhythm effects (Hayashi et al., 2001).
At the laboratory, all leaves were removed from stems, they were
recut under distilled water and their length was measured before
distribution at random among treatments. The experiments were
conducted in a vase life evaluation room at 22
±
1 ◦C, 60
±
10% relative
humidity (RH) and 12 mol/m2/s light intensity from cool
white fluorescent tubes on a daily 12 h light period. The treatments
were replicated in individual plastic vases, each containing 200 mL
of a vase life solution (containing 10 L L−1 free active chlorine) as
adapted from Xie et al. (2008). Each vase mouth was covered with
aluminium foil to prevent solution evaporation. A small slit in the
foil covers accommodated the stem/s. The vases were arranged on
benches in a randomised complete block design