二型葉蕨類假紫萁營養葉與孕性葉之物候差異

Phenological Differences between Sterile and Fertile Fronds in a Dimorphic Fern, Osmundastrum cinnamomeum (L.) C.Presl (Osmundaceae)

假紫萁為二型葉蕨類，其營養葉與孕性葉外觀形態差異大，本研究選擇台灣東北部草埤濕地假紫萁進行為期一年之物候調查（2009年2月－2010年1月），比較兩種葉子物候差異。在所調查的80個樣株，所有孕性葉集中在3月抽芽，營養葉抽芽期從4月至9月；孕性葉抽芽月份之月均溫、白天長度及日輻射能均比營養葉抽芽月份來得低。孕性葉葉片壽命僅一個月左右，營養葉則具有較長的壽命，平均6.3±1.5個月，另外，營養葉壽命長短與抽芽時間有關，愈接近生長季初期抽芽之葉片壽命愈長，反之，愈接近末期抽芽之葉片壽命愈短。

Osmundastrum cinnamomeum (L.) C.Presl (Osmundaceae) is a dimorphic fern with distinct morphology in its sterile and fertile fronds. This study investigated phenology of O. cinnamomeum at Cao-Pi wetland in northeastern Taiwan from February 2009 to January 2010, comparing the phonological difference between sterile and fertile fronds. Among the 80 sampled plants, all fertile fronds emerged in March, whereas sterile fronds emerged from April to September. The mean monthly temperature, day length and daily solar radiation during the period of the emergence of fertile fronds were both lower and shorter than those of the sterile fronds. The life span of fertile fronds was ca. 1 month, much shorter than that of sterile fronds (ca. 6.3±1.5 months). Additionally, those sterile fronds emerging early in the growing season usually had longer life span than those emerging later.