Stem elongation and keeping quality in poinsettia (Euphorbia pulcherrima Willd.) as affected by temperature and supplementary lighting

摘要: Abstract Euphorbia pulcherrima cultivars ‘Lilo’ and ‘Starlight’ were grown under five different day/night temperature (DT/NT) regimes from the start of short days (SD) to flowering for two starting periods, 1 October (replicate A) 12 B). The average daily (ADT) was kept at 18–20°C. Plants given supplementary lighting with high pressure sodium lamps (HPS) 10 h day −1 three photosynthetic photon flux densities (PPFD): 12, 37 73 mol m −2 s . At marketing stage plants moved interior holding room testing keeping quality. Both plant height diameter lower when DT NT (positive DIF) or constant (zero DIF). response DIF stronger in replicate A than B, considerably greater ‘Lilo’. Negative DIF-grown resulted delayed visible cyathia compared zero positive DIF. flowered earliest. reached about week earlier lighting.