Oxaloacetate as the Source of Carbon Dioxide for Photosynthesis in Bundle Sheath Cells of the C(4) Species Panicum maximum |
| |
Authors: | Ray T B Black C C |
| |
Institution: | Department of Botany, University of Georgia, Athens, Georgia 30602. |
| |
Abstract: | 3-Mercaptopicolinic acid (3-MPA), an inhibitor of phosphoenolpyruvate carboxykinase, was employed to study the role of organic acid decarboxylation during C(4) photosynthesis. Treatment of detached Panicum maximum leaves with 5 mm 3-MPA inhibited photosynthesis 70 to 75%. Oxygen was found to have no effect on the degree of inhibition. The postillumination (14)CO(2) burst associated with P. maximum photosynthesis was almost abolished by 5 mm 3-MPA. The turnover rates of malate and aspartate during C(4) photosynthesis were severely reduced as well as the rates of formation of C(3) cycle intermediates in P. maximum leaves treated with 3-MPA. These results are interpreted as direct evidence for the fixation of CO(2), arising from the decarboxylation of oxaloacetate, by the C(3) cycle in bundle sheath cells of P. maximum leaves. |
| |
Keywords: | |
本文献已被 PubMed 等数据库收录! |
|