不同光量下小扭口苔氣體交換與葉綠素螢光之研究

Study on the Gas Exchange Quantitative and Chlorophyll Fluorescence of Barbula indica under Different Irradiations

"本研究量測小扭口苔（Barbula indica（Hook.）Spreng.）於不同光量梯度下之氣體交換及葉綠素螢光參數，發現小扭口苔因不具有氣孔構造，呈現蒸散速率與光合作用速率無論處於何種光量下，蒸散速率皆維持固定速率（約21 mmol H_2O m^(-2) s^(-1)）。同時具有較高的光飽和點（light saturation point, LSP at 800-1,200μmol photon m^(-2) s^(-1)）及光補償點（light compensation point, LCP at 68.19±12.36μmol photonm^(-2) s^(-1)），以及較低的暗呼吸速率（dark respiration rate, Rd at 3.31±0.48μmol CO_2 m^(-2) s^(-1)），這或許其為廣布型的原因之一。在光化學效能（electron transport rate, ETR）方面，ETR與光合速率（net photosynthesis rate, Pn）呈現顯著相關（P＜0.0001），且高光下（1,200-2,000μmol photon m^(-2) s^(-1)），非光化學消散（non-photochemical quenching, NPQ）能量比例佔全部能量之80%，顯示小扭口苔的光合系統已具有相當功能性的非光化學消散機制，藉由葉綠素螢光量測的技術，具方便、快速及非破壞性等優點，可藉此監測苔蘚植物生態生理的狀態，有助了解光合系統的演進，並開發新的應用於這類廣泛存在的苔蘚植物。"

"The gas exchange and chlorophyll fluorescence parameters of Barbula indica (Hook.) Spreng. were measured under different irradiation gradients. The results show that B. indica is lack of stomatal structure, and regardless of the amount of irradiation, the evapotranspiration rate maintained a constant rate around 21 mmol H_2O m^(-2) s^(-1). B. indica had a higher light saturation point at 800-1,200μmol photon m^(-2)s^(-1) and a light compensation point at 68.19±12.36μmol photonm^(-2) s^(-1), and low dark respiration rate at 3.31±0.48μmol CO_2 m^(-2) s^(-1)). This may be one of the reasons for the widespread type. In terms of photochemical efficiency, ETR of B. indica was significantly correlated with photosynthetic rate (P＜0.0001). Under high light at 1,200-2,000μmol photon m^(-2) s^(-1), the proportion of non-photochemical quenching energy accounted for 80% of the total energy, indicating that the photosynthetic system of B. indica was capable with the functional non-photochemical quenching mechanism. The chlorophyll fluorescence measurement technology has not only the advantages of convenience, speed, and non-destructiveness which can monitor the ecological and physiological state of moss, but also will help understand the evolution of the photosynthetic system and develop new applications for such widespread moss."