MAGNESIUM ACTIVATION OF PHOTOSYNTHETIC CO 2 ‐FIXATION IN A RECONSTITUTED CHLOROPLAST SYSTEM
S ummary Measurements of O 2 ‐evolution by a reconstituted chloroplast system showed that photosynthetic electron transport and 3‐phosphoglycerate reduction proceed at rapid rates in the presence of 0.5‐1 ran MgCl 2 . However, to obtain maximal rates of CO 2 ‐dependent O 2 ‐evolution under these con...
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| Published in | The New phytologist Vol. 73; no. 4; pp. 657 - 662 |
|---|---|
| Main Authors | , , |
| Format | Journal Article |
| Language | English |
| Published |
01.07.1974
|
| Online Access | Get full text |
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| Summary: | S
ummary
Measurements of O
2
‐evolution by a reconstituted chloroplast system showed that photosynthetic electron transport and 3‐phosphoglycerate reduction proceed at rapid rates in the presence of 0.5‐1 ran MgCl
2
. However, to obtain maximal rates of CO
2
‐dependent O
2
‐evolution under these conditions, it was necessary to increase the Mg concentration to 5 mM (70‐90% of the maximum rate was observed at 2.5 mM Mg). Rapid rates of CO
2
‐dependent O
2
evolution were also recorded at 1 mM Mg when the bicarbonate concentration was increased from 1 to 40 mM. Simultaneous measurements of
14
CO
2
fixation and O
2
evolution in the presence of ribulose‐1, 5‐diphosphate confirmed that the additional Mg was required for the carboxylation step and showed that the Mg activation was a more rapid process than the kinetics of CO
2
‐dependent O
2
evolution might suggest. |
|---|---|
| ISSN: | 0028-646X 1469-8137 |
| DOI: | 10.1111/j.1469-8137.1974.tb01292.x |