Reappraisal of the Role of Sodium in the Light-Dependent Active Transport of Pyruvate into Mesophyll Chloroplasts of C4 Plants
| Autor: | Ryuzi Kanai, Naohiro Aoki |
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| Rok vydání: | 1997 |
| Předmět: | |
| Zdroj: | Plant and Cell Physiology. 38:1217-1225 |
| ISSN: | 1471-9053 0032-0781 |
| DOI: | 10.1093/oxfordjournals.pcp.a029108 |
| Popis: | + on the active transport of pyruvate in meso- phyll chloroplasts of Panicum miliaceum, a Na + -type C4 species, by comparing the rate of pyruvate uptake at vari- ous external pHs under four conditions; in the light and dark together with/without Na + -jump: (1) At neutral pH, the rate of pyruvate uptake in the dark was enhanced by Na + -jump but scarcely by illumination. (2) While the en- hancement effect by Na + -jump was independent of exter- nal pH, that by illumination increased greatly at pH over 7.4, and the effects of light and Na + at the alkaline pH were synergistic. (3) The light-enhanced pyruvate uptake was re- lated to stromal alkalization induced by illumination. In fact, pyruvate uptake was induced by H + -jump in the medi- um from pH 8.0 to 6.7. (4) Stromal pH was lowered by the addition of K + -pyruvate and more by Na + -pyruvate into the medium at pH 7.8 in the light. (5) However, the pH and ATP levels in the stroma were not affected by Na + -jump. |
| Databáze: | OpenAIRE |
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