Fertilization and night temperature effects on growth and carbohydrate status of poinsettia

Poinsettia (Euphorbia pulcherrima Willd ’Annette Hegg Dark Red’) were fertilized with 3.0, 4.5 or 6.0 g per 15-cm pot of Osmocote (14N-6.1P-11.6K) and were grown in greenhouses at 9, 13, or 17 °C night temperature. As the night temperature increased, the number of days to anthesis, bract number and carbohydrate levels decreased. Maximum bract mean area and minimum root dry weight were achieved at 13 °C. High fertilizer rates increased the number of days to anthesis while bract number, root and shoot dry weights, reducing and total sugar content decreased.Key words: Euphorbia pulcherrima, fertilization, night temperature, carbohydrate