Melatonin was found in the fresh water characeae Chara australis. The concentrations (~4 μg/g of tissue) were similar in photosynthesizing cells, independent of their position on the plant and rhizoids (roots) without chloroplasts. Exogenous melatonin, added at 10 μM to the artificial pond water, increased quantum yield of photochemistry of photosystem II by 34%. The increased efficiency appears to be due to the amount of open reaction centers of photosystem II, rather than increased efficiency of each reaction center. More open reaction centers reflect better functionality of all photosynthetic transport chain constituents. We suggest that melatonin protection against reactive oxygen species covers not only chlorophyll, but also photosynthetic proteins in general.
- MeSH
- Antioxidants metabolism pharmacology MeSH
- Chara drug effects metabolism MeSH
- Characeae MeSH
- Chlorophyll metabolism MeSH
- Chloroplasts MeSH
- Photosynthesis * drug effects MeSH
- Photosystem II Protein Complex metabolism MeSH
- Melatonin metabolism pharmacology MeSH
- Reactive Oxygen Species metabolism MeSH
- Light-Harvesting Protein Complexes metabolism MeSH
- Electron Transport * drug effects MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
