不同溫度及種子大小對聖誕紅種子萌芽率之影響

Abstract

Plant internode of poinsettia seeding is longer than that of cutting and the seedlings are vigor and grown faster. Taking these advantages of seedlings for tree poinsettia production could reduce the labor cost of axillaries or leaf removal on the trunk. The emergence percentage of poinsettia seeds is 64.0%before grading the seeds to large (>5.0 mm), medium (4.75-5.0 mm) and small (<4.75mm), the emergence percentage of large seed could be improved to 71.0%. Seeds emergence at 25℃ could be improved than 80%, but the germination percentage and cotyledon opening percentage will decrease when sowing temperature is excess 28℃,as well as was only 30% when seeds sowing at 34℃. Consequently, 28℃ is the maximum temperature that appropriate for poinsettia seeds sowing.聖誕紅之實生苗較扦插苗的節間長、生長快且強健，以實生苗作為樹型聖誕紅之生產方式，便可省去一般生產樹型聖誕紅去除側芽與摘除主幹葉片的時間及勞力耗費。但聖誕紅種子萌芽率差，將種子分級成大(＞5.0mm)、中(5.0-4.75mm)、小(＜4.75mm)3級，分級後大種子的萌芽率可提高至71.0%。25℃聖誕紅播種最適溫度，其萌芽率可達80%以上，當播種溫度超過28℃聖誕紅種子之萌芽率及子葉張開率即有下降的趨勢，34°C播種時萌芽率及子葉張開率更僅有30%，可見28為適於聖誕紅種子播種的上限溫度