Argeranthemumfrutescens `Butterfly' and `Sugar Baby', Brachycomehybrid `Ultra', Helichrysumbracteatum `Golden Beauty', Scaevolaaemula `New Wonder',Supertuniaaxillaris hybrids `Kilkenny Bells' and `Pink Victory', Suteracordata `Mauve Mist' and `Snowflake', and Verbenahybrid `Blue' were grown in a glass greenhouse maintained at 20°C under seven different photoperiods (10-, 12-, 13-, 14-, 16-, 24-hr, and 4-hr night interruption). Black cloth was pulled at 1700 and opened at 0800 HR; incandescent lamps provided 2 μmol·m–2·s–1 to extend light hours to the designed photoperiods. Seedlings were pinched 3 days after transplant. Responses to photoperiod were clearly species-dependent. The tested species can be classified into three groups: 1) stem elongation and flowering were promoted in the long-day treatment (A.frutescens and S. axillaris hybrids), 2) only stem elongation was promoted in the long-day treatment (S. aemula, H. bracteatum, and B. hybrid), and 3) neither flowering nor stem elongation were affected by photoperiod (S. cordata and V. hybrid).
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