Color Expression, Pigment Composition, and Related Gene Transcription in Double Coloring Petals of Cut Roses

This study was conducted to investigate the bicolor expression in petals of double coloring cut roses due to temperature stress. Plant materials were grown in controlled growth cabinets at 25/18°C AT and 65% RH in the lighting condition of 800 μmol•m^-²•s^-1 PAR of 16hr photoperiod. The treatments of high temperature stress (39/18°C, HTS) and low temperature stress (25/6°C, LTS) were applied during 3 days just before petal coloring as the most susceptible development stage to air temperature. HTS had directly affected the petal growth as well as color expression, while LTS hadn’t significantly induced the change in petal development or coloring. Both color expression and anthocyanin content in petals had been seriously diminished by HTS, 24.7% and 64.6%, respectively. Two anthocyanidins detected by HPLC had changed in the ratio according to temperature stress. To know the mechanism for decolorization in double coloring cut roses, the pigmentation-related gene expression was detected by qRT-PCR.