川上氏月桃（薑科）開花物候與授粉生態學研究

Flowering phenology and pollination ecology of Alpinia shimadae var. kawakamii (Zingiberaceae)

本研究以臺灣特有變種川上氏月桃（Alpinia shimadae var. kawakamii）為對象，觀察其開花物候、開花行為，以及授粉者行為與拜訪數量。位於南投國姓後角寮地區的川上氏月桃在2011- 2012年觀察結果，成熟假莖於1月初開始發育花苞，3-5月為其開花期；開花後約1-2週子房逐漸膨大發育成果實，10月時果壁由綠色轉為紅色而成熟，12月至隔年1月蒴果開裂露出種子。開花行為觀察證實川上氏月桃具花柱捲曲性（flexistyly），單花開放時間約為1日，開花時花柱上舉型之柱頭先於00:00-08:00處於下位位置，隨後花柱迅速上彎並於09:00-11:00柱頭位置高於花藥，花藥在11:00- 13:30開裂；花柱下垂型則於00:00-13:00柱頭處於上位位置，並於03:00-03:30花藥開裂，中午花柱開始下彎至12:30-14:00柱頭處於下位位置，花柱上舉型與花柱下垂型的花藥皆在自身柱頭進入上位1-4 小時後開裂，減少自花授粉和同表現型間授粉的機會。觀察研究發現，蜜蜂科（Apidae）的精選熊蜂（Bombus eximius）與螯無墊蜂（Amegilla urens）為川上氏月桃的主要授粉者，其中精選熊蜂在上午 07:00-09:00、下午15:00-17:00出現訪花高峰，這些時期與柱頭下位的雌性階段和花粉出現的雄性階段配合，花柱捲曲性的開花行為特性與授粉者的訪花習性相互配合促進授粉效率。 In this study, we observed the flowering phenology, flowering behaviour, pollinator's behaviour and visiting frequency of Alpinia shimadae var. kawakamii which is a Taiwanese endemic variety. We generalized from the phenological observation in Houjiaoliao study area in 2011-2012. Al. shimadae var. kawakamii began developing flower buds in early January, and started anthesis last 2 months in late March. The ovary gradually developed into fruit after flowering 1-2 weeks, the color of fruit wall converted from green to red and matured in October to December, capsule dehisced and seeds exposed in December to following January. The observation of flowering behaviour confirms Al. shimadae var. kawakamii also possesses flexistyly, its single flower anthesis is about 1 day. The anaflexistylous stigma below the anther was during 00:00-08:00, then the style rapidly incurved and the stigma above the anther at 09:00-11:00, and the anther dehisced about 11:00-13:30; the cataflexistylous stigma above the anther is during 00:00- 13:00, the anther dehisces at 03:00-03:30, the style started recurving at moon then the stigma situated below the anther after 12:30-14:00. Both anthers of two phenotypes dehisced after its own stigma into the upper position for 1-4 hours, that reduces the chance of self-pollination and intramorph-pollination. We found Bombus eximius and Amegilla urens (Apidae) were pollinators of Al. shimadae var. kawakamii. Bombus eximius had higher visiting frequency during 07:00-09:00 and 15:00-17:00, those periods corresponded with female phase and male phase of flower. The cooperation between the flowering behaviour of flexistyly and the habits of pollinators promotes the efficiency of pollination.