芋葉片光合作用特性之研究

Studies on the Photosynthetic Characteristics of ＂Colocasia esculenta＂ Schott L. Leaf

蕭政弘(Cheng-Hung Hsiao) ； 陳葦玲(Wei-Ling Chen) ； 黃威儒(Wei-Ru Huang)

《臺中區農業改良場研究彙報》 124期 (2014/09) Pp. 17-27

摘要

為瞭解芋（Colocasia esculenta Schott L.）葉片光合作用特徵，以株齡4個月之芋‘高雄一號’植株為材料，利用光合作用測定儀LI-6400XT測定光強度、二氧化碳濃度、葉齡及於白天14小時中對其光合作用速率與相關生理反應。由光反應曲線可知芋‘高雄一號’之光補償點、光飽合點及最大淨光合作用速率分別為30μmol．M^(-2)s^(-1)、1,000μmol．M^(-2)s^(-1)及12～13μmol CO_2．M^(-2)s^(-1)。由CO_2反應曲線可知CO_2飽合點為1,200ppm，此時之淨光合作用速率為20μmol CO_2．M^(-2)．S^(-1)、較正常大氣下之濃度（400ppm）之9.5μmol CO_2．M^(-2)s^(-1)增加約2.1倍。晴天下於上午7點即到達高峰，並維持到下午4點，淨光合作用速率值約為13～14μmolCO_2．m^(-2)s^(-1)而後明顯下降。七天齡芋葉其光合作用速率約為13μmol m^(-2)s^(-1)，14天齡葉片光合作用速率下降至12μmol m^(-2)s^(-1)。並在第21、28天回升至13μmol m^(-2)s^(-1)接著第35天時會再次降低至11μmol m^(-2)s^(-1)。葉片氣孔導度在第35天顯著上升，蒸散速率及葉肉間隙二氧化碳濃度在第7天到21天差異不顯著，但到第28、35天亦顯著上升。

關鍵字

芋 ； 光合作用 ； 光強度 ； 二氧化碳 ； 葉齡

並列摘要

In order to understand the photosynthetic characteristics of taro (Colocasia esculenta Schott L), four month old taro 'Kaoshung No. 1' plants grown in TDARES was used as experimental materials. The effect of light intensity, carbon dioxide concentration, leaf age and diurnal changes on net photosynthetic rate (Pn) and its related physical responses were studied. The results indicated that the light compensation point, light saturation point and maximum net photosynthetic rates of taro leaves were 30μmol m^(-2)s^(-1), 1,000μmol m^(-2)s^(-1), and about 12~13μmol CO_2 m^(-2)s^(-1), respectively. The CO_2 response curve showed that the CO_2 saturation point was 1,200ppm while the net photosynthetic rate was 20μmol CO_2 m^(-2)s^(-1), which was 2.1 times higher than that of atmosphere control (400ppm). The diurnal changes of Pn reached the first peak at 7:00 am and maintained stable around 13~14μmol CO_2 m^(-2)s^(-1) until 4:00 pm and then decreased significantly. The Pn value of 7 days-old taro leaves was 13μmol m^(-2)s^(-1), however, the Pn of 14 days-old leaves decreased to 12μmol m^(-2)s^(-1) and then raised back to 13μmol m^(-2)s^(-1) when the leaves growing to 21 and 28 days old. Photosynthetic rate declined to 11μmol m^(-2)s^(-1) again on the leaves of 35 days-old, and the stomatal conductance increased at the same time. No significant difference was found on transpiration rate and intercellular CO_2 concentration among 7 to 21 days-old leaves, however, both transpiration rate and intercellular CO_2 concentration were increased at 28 and 35 days old leaves.

並列關鍵字

Taro ； Photosynthesis ； Light Intensity ； Carbon Dioxide ； Leaf Age