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Pathways of Carbohydrate Catabolism in Senescent and Non‐senescent Tobacco Leaves
Author(s) -
Baur J. R.,
Halliwell R. S.,
Langston Ruble
Publication year - 1968
Publication title -
physiologia plantarum
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.351
H-Index - 146
eISSN - 1399-3054
pISSN - 0031-9317
DOI - 10.1111/j.1399-3054.1968.tb07229.x
Subject(s) - pentose phosphate pathway , hexose , catabolism , biochemistry , chemistry , pentose , carbohydrate metabolism , carbohydrate , ribose , metabolism , metabolic pathway , glycolysis , biology , enzyme , fermentation
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‐ 14 C and C 6 /C 1 ratios were computed from the radioactivity of 14 CO 2 collected. Two methods of calculation were compared. Hexose monophosphate pathway activity was also compared in both ages of tissue by measuring 14 CO 2 respired from substrate ribose‐1‐, xylose‐1‐ and gluconic acid‐6‐ 14 C. The results indicate that the hexose monophosphate pathway accounts for approximately 25 percent of the respired CO 2 in both senescent and non‐senescent tissues. Both types of tissue were equally efficient in degrading HMP shunt intermediates to CO 2 .