title: Exogenous melatonin affects photosynthesis in characeae Chara australis.
abstract: 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.
authors.affiliation: Department of Biophysics; Centre of the Region Haná for Biotechnological and Agricultural Research; Faculty of Science; Palacký University; Olomouc, Czech Republic.
authors.forename: Dušan
authors.initials: D
authors.lastname: Lazár
authors.forename: Susan J
authors.initials: SJ
authors.lastname: Murch
authors.forename: Mary J
authors.initials: MJ
authors.lastname: Beilby
authors.forename: Sabah
authors.initials: S
authors.lastname: Al Khazaaly
mesh_terms: D000975:Antioxidants / Q000378:metabolism* / Q000494:pharmacology; D044784:Chara / Q000187:drug effects / Q000378:metabolism*; D044522:Characeae; D002734:Chlorophyll / Q000378:metabolism; D002736:Chloroplasts; D004579:Electron Transport / Q000187:drug effects; D045342:Light-Harvesting Protein Complexes / Q000378:metabolism*; D008550:Melatonin / Q000378:metabolism* / Q000494:pharmacology; D010788:Photosynthesis / Q000187:drug effects; D045332:Photosystem II Protein Complex / Q000378:metabolism*; D017382:Reactive Oxygen Species / Q000378:metabolism
chemical_list: D000975:Antioxidants; D045342:Light-Harvesting Protein Complexes; D045332:Photosystem II Protein Complex; D017382:Reactive Oxygen Species; D002734:Chlorophyll; D008550:Melatonin
keywords: Characeae; antioxidants; chlorophyll fluorescence; melatonin; photosynthesis; reactive oxygen species