| 摘要: | 台灣位於歐亞大陸邊緣的太平洋上，北迴歸線通過嘉義附近，將台灣劃分為北迴歸線以北之副熱帶和以南之熱帶兩大區域，跟熱帶地區與亞北極地區相比，台灣副熱帶高海拔地區高山氣候特殊，有著涼爽的夏季與溫暖的冬季特性。為了比較不同海拔及季節下藻類之光系統II 效能 (photosystem II efficiency, ΦPSII) 在溫度和光度下的反應及釋氧量差異，選擇在台灣不同海拔湖泊內之藻類為材料，於2009年7月起至2010年2月止，我們選擇了五個湖泊，分別在天池 (2620 m a.s.l.)、翠峰湖 (1840 m a.s.l.)、鴛鴦湖 (1670 m a.s.l.)、台中公園日月湖 (78 m a.s.l.) 及中興湖 (70 m a.s.l.) 測定不同光量子流密度 (photosynthetic photon flux density, PPFD) 與不同溫度下之葉綠素螢光 (chlorophyll fluorescence) 與釋氧量 (O2 evolution, OE)。結果顯示，藻類之 PSII 效能會隨著光度的增加呈曲線遞減，而且在高光或低溫情況下遞減的情況會更加劇烈。而 PSII 效能之光曲線能藉由複迴歸方程式進行五地不同海拔湖泊藻類之 PSII 效能之推估。在相同季節下，高海拔比低海拔之藻類容易在高溫時 PSII 效能向下調節，下降斜率變大，而低海拔之藻類變化不大。在低溫時高海拔之藻類 PSII 效能下降較快，降低光合作用效率，使減輕過剩光能之傷害。而不同海拔湖泊之藻類在不同季節及溫度下其電子傳遞速率 (electron transport rate, ETR) 之變化情形，會隨 PPFD 之增加而呈指數曲線上升，其幅度在低 PPFD 較大，隨著 PPFD 增加，其上升幅度逐漸變緩。其釋氧量之結果顯示不同海拔湖泊之藻類在三個溫度下，其釋氧量大都會隨 PPFD 之增加而呈曲線上升。藻類其溫度每增加10 ℃ 時，藻類呼吸速率增加之倍率 (Q10) 大致隨海拔下降而減少，低海拔有較低的 Q10。不同海拔湖泊所產之藻類，在不同溫度下，當 PPFD 增加時，其 ETR 均隨釋氧量增加而直線上升，兩者間呈顯著直線正相關，天池、翠峰湖，中興湖在各季節個溫度下均呈相同趨勢，而鴛鴦湖及台中公園，則呈季節差異。
High elevation of sub-tropical Taiwan have cool summer and warm winter compared with temperature and subarctic regions. In order to understand the response of photosystem Ⅱ efficiency (ΦPSⅡ) to variable temperature and light intensity, as well as the response of O2 evolution to temperature of microalgae, in this study, we selected five lakes, i.e. : Chung-Hsing Lake (70 m a.s.l.), Riyun Lake (78 m a.s.l.), Yuan-Yang Lake (YYL, 1670 m a.s.l.), Emerald Peak Lake (1840 m a.s.l.), Tianchi (2620 m a.s.l.) to study the chlorophyll fluorescence and O2 evolution of the different photosynthetic photon flux density (PPFD) and variable temperature from July 2009 to February 2010. Results indicated that ΦPSⅡ of microalgae decreased curve-linearly with increasing irradiance, and this decrease was more drastic under low temperature and high irradiance. Light response curve of ΦPSⅡof the multiple regression equations for the five lakes at different altitudes could to estimate the ΦPSⅡ of microalgae. In the same season, the ΦPSⅡ of microalgae would down-regulation at high temperatures that is easier at low altitudes than at high altitudes, the decline of slope is strong. At low temperatures and high altitudes, ΦPSⅡ of microalgae decreased faster, and then decrease the photosynthetic efficiency to reduce the damage of excess energy of light. The electron transport rate (ETR) of microalgae to different seasons and variable temperature decreased curve - exponentially with increasing irradiance, and it gradually decreases the rate when the PPFD increased.
Results of O2 evolution indicated that sample from three temperatures, the O2 evolution increased curve-linearly with PPFD increased. Respiratory rate of microalgae generally decreased with altitude, low elevation showed lower Q10. Indicating that respiration of microalgae grown at low elevation of sub-tropical Taiwan was lower sensitivity to high temperature. ETR increased linearly with increasing O2 evolution when PPFD increased. Tianchi、Emerald Peak Lake and Chung-Hsing Lake showed the similar trend in all seasons. Yuan-Yang Lake and Riyun Lake were difference in seasonal and temperature. |
