Photosynthesis in enzymatically isolated leaf cells from the CAM plant Sedum telephium L. |
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Authors: | Martin H. Spalding Gerald E. Edwards |
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Affiliation: | (1) Horticulture Department, University of Wisconsin, 53706 Madison, WI, USA |
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Abstract: | A technique has been developed for the enzymatic isolation of leaf cells from the Crassulacean acid-metabolism plant Sedum telephium. The cells exhibited high activity in both 14CO2 incorporation (30–70 mol CO2 mg-1 chlorophyll h-1) and O2 evolution in the presence of bicarbonate (60–110 mol O2 mg-1 chlorophyll h-1). Half-maximum saturation of 14CO2 incorporation occurred at a bicarbonate concentration of ca. 2 mM (20 M CO2) at pH 8.4 and 30°C. Two types of light-dependent O2 evolution are reported: O2 evolution in the absence of exogenously supplied bicarbonate (endogenous O2 evolution), and bicarbonate-stimulated O2 evolution. Oxygen evolution in the presence of approximately ambient concentrations of CO2 appeared to be a combination of the endogenous O2 evolution and O2 evolution from fixation of the exogenously supplied CO2.Abbreviations CAM Crassulacean acid metabolism - cirlo chlorophyll - DCMU 3-(3,4-dichlorophenyl)-1,1-dimethylurea - PEP phosphoenolpyruvate - RuDP ribulose-1,5-diphosphate |
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Keywords: | Crassulacean acid metabolism (CAM) Oxygen evolution (photosynthesis) Photosynthesis Sedum |
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