Influence of photoperiod, photosynthetic photon flux, and temperature on growth of Canary Island ivy

The effects of selected environmental factors [temperature, photosynthetic photon flux (PPF), and photoperiod] that contribute to optimal vegetative growth of Canary Island ivy (Hedera canariensis Willd.) were investigated. Experiments were conducted in growth chambers at constant day/night temperatures of 16 and 26 °C. The greatest number of leaves (6.1) and plant height (38.0 cm) were achieved with PPF of 210 μmol · m^-2 · s^-1 and an 8-hour photoperiod at 16 °C. The greatest branch number (3.9), leaf area (41.4 cm²) and leaf chlorophyll content (1.02 mg · cm^-2) were achieved with a PPF of 210 μmol · m^-2 · s^-1 with a 12-hour photoperiod at 16 °C. Under normal greenhouse or field conditions, Canary Island ivy rarely branches; however, a PPF of 210 μmol · m^-2 · s^-1 also induced branching.