二氧化碳濃度與溫度對樟樹苗木之形質生長參數與葉綠素螢光反應之影響

Effects of Carbon Dioxide Concentrations and Temperatures on Performance Growth Parameters and Chlorophyll Fluorescence Kinetics in Cinnamomum camphora Seedlings

本研究旨在探討提高二氧化碳濃度與溫度處理對樟樹（Cinnamomun camphora）苗木之生長與葉綠素螢光反應的影響。苗木生長於開放式玻璃生長箱，分別施以385±3 ppm（大氣，C3）或696±17 ppm（C7）二種二氧化碳濃度及28℃ / 23℃（常溫，T2）或32℃ / 23℃（T3）二種日／夜溫度等四種處理，為期8週。在形質生長表現方面，高溫處理（C3T3 或C7T3）對各種形質生長表現稍具促進效果。高二氧化碳濃度環境下（C7T2），亦可促進苗木的早期生長，而處理後期促進效果則趨緩。高二氧化碳濃度與高溫對葉片數目、單葉面積與根、莖、葉部乾物重均有增加的趨勢；而比葉面積因葉部乾物重增加或葉片變厚而降低，並與大氣二氧化碳濃度下常溫或高溫處理者間無顯著差異。在葉綠素螢光反應方面，處理初期，各種處理條件之PSII 最初光能轉化效率（Fv/Fm）與PSII 潛在活性（Fv/Fo）均隨著幼苗的生長而呈現增加的現象。處理後期，高二氧化碳濃度（C7T2）致使PSII 最初光能轉化效率、PSII 潛在活性、光化學淬熄係數（qP）與光量子產量（yield）降低，而非光化學淬熄係數（qN）增加。高二氧化碳濃度與高溫之葉綠素螢光反應參數，則與大氣二氧化碳濃度下常溫或高溫處理者無顯著差異。研究結果顯示：高二氧化碳與高溫處理對形質生長表現之促進效果較單獨處理高溫或高二氧化碳者為佳，且由葉綠素螢光反應之結果而言，其對光合作用光反應之影響不如高二氧化碳處理者顯著，表示高溫條件能夠影響高二氧化碳之處理效果。 This study was to investigate the effects of elevated carbon dioxide concentration and temperature on the growth and chlorophyll fluorescence in camphor (Cinnamomun camphora) seedings. Seedlings grown in 1.25 m3 open-top chamber, were treated with two different carbon dioxide concentrations ( 385±3 ppm, ambient, C3, or 696±17 ppm, elevated, C7 ) and day/night temperatures ( 28℃ / 23℃, ambient, T2 or 32℃ / 23℃, higher, T3 ) for eight weeks. Growth was enhanced by higher temperature, either in ambient (C3T3) or elevated (C7T3) carbon dioxide concentrations. However, in high concentration of carbon dioxide (C7T2), growth was observed enhanced in early a few weeks, then not observed later. The numbers of leaf, single leaf area, and dry matter of seedling increased, and specific leaf area decreased under the condition of high carbon dioxide concentration and temperature. Furthermore, there was no significant difference between ambient and higher temperature under ambient carbon dioxide concentration. In the respect of chlorophyll fluorescence kinetics during the earlier treatment, the primary efficiency of light conversion of PSⅡ (Fv/Fm) and potential activity of PSⅡ (Fv/Fo) were enhanced in each treatment. However, under elevated carbon dioxide concentration, the primary efficiency of light conversion of PSⅡ, potential activity of PSⅡ, photochemical quenching coefficient (qP) and quantum yield (yield) were decreased, while non-photochemical quenching coefficient (qN) was increased. It showed that light reactions of photosynthesis of camphor seedlings were highly affected by elevated carbon dioxide concentration.

This study was to investigate the effects of elevated carbon dioxide concentration and temperature on the growth and chlorophyll fluorescence in camphor (Cinnamomun camphora) seedings. Seedlings grown in 1.25 m3 open-top chamber, were treated with two different carbon dioxide concentrations ( 385±3 ppm, ambient, C3, or 696±17 ppm, elevated, C7 ) and day/night temperatures ( 28℃ / 23℃, ambient, T2 or 32℃ / 23℃, higher, T3 ) for eight weeks. Growth was enhanced by higher temperature, either in ambient (C3T3) or elevated (C7T3) carbon dioxide concentrations. However, in high concentration of carbon dioxide (C7T2), growth was observed enhanced in early a few weeks, then not observed later. The numbers of leaf, single leaf area, and dry matter of seedling increased, and specific leaf area decreased under the condition of high carbon dioxide concentration and temperature. Furthermore, there was no significant difference between ambient and higher temperature under ambient carbon dioxide concentration. In the respect of chlorophyll fluorescence kinetics during the earlier treatment, the primary efficiency of light conversion of PSⅡ (Fv/Fm) and potential activity of PSⅡ (Fv/Fo) were enhanced in each treatment. However, under elevated carbon dioxide concentration, the primary efficiency of light conversion of PSⅡ, potential activity of PSⅡ, photochemical quenching coefficient (qP) and quantum yield (yield) were decreased, while non-photochemical quenching coefficient (qN) was increased. It showed that light reactions of photosynthesis of camphor seedlings were highly affected by elevated carbon dioxide concentration.