Pathways of Carbohydrate Catabolism in Senescent and Non-senescent Tobacco Leaves |
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Authors: | J R Baur R S Halliwell Ruble Langston |
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Institution: | Department of Plant Sciences, Texas A&M University, College Station, Texas |
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Abstract: | The pathway (s) of glucose degradation in detached senescent and non-senescent tobacco leaves from plants approximately 100 days old were studied utilizing‘Relabeled carbohydrates. Comparable samples of each tissue were allowed to metabolize glucose-1- and glucose-6-14C and C6/C1 ratios were computed from the radioactivity of 14CO2 collected. Two methods of calculation were compared. Hexose monophosphate pathway activity was also compared in both ages of tissue by measuring 14CO2 respired from substrate ribose-1-, xylose-1- and gluconic acid-6-14C. The results indicate that the hexose monophosphate pathway accounts for approximately 25 percent of the respired CO2 in both senescent and non-senescent tissues. Both types of tissue were equally efficient in degrading HMP shunt intermediates to CO2. |
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