关键词: 一品红（Euphorbia pulcherrima Willd. et Kl.）, 短日照, 海拔高度, 苞片着色

Abstract: The experiment was conducted to study the effects of short sunshine treatment on bracts of four different poinsettia（Euphorbia pulcherrima Willd. et Kl.） cultivars at different altitudes in Enshi including Gold prize, Sunshine, Flag 1, Flag 2, so the optimum altitude and the best varieties suitable for red poinsettia bracts could be obtained. The results showed that the altitude of 800 to 1 080 meters was the best location of poinsettia short-day treatment. The growth of four different varieties of poinsettia in the same altitude condition was not obvious, but at the different altitude was obvious. The growth conditions of the Gold prize was better than that of the others. The final results suggested, at the altitude of 800 to 1 080 meters, the effect was the best for the short-day treatment of Gold prize.

Key words: poinsettia（Euphorbia pulcherrima Willd. et Kl.）, short-day, altitude, bract pigmentation