Light driven redox changes of cytochrome f and the development of photosystems I and II during greening of bean leaves
| Autor: | Roger G. Hiller, N.K. Boardman |
|---|---|
| Rok vydání: | 1971 |
| Předmět: |
Light
Photosystem II Infrared Rays Biophysics Plant Development Photochemistry Photosystem I Biochemistry Electron Transport chemistry.chemical_compound Plant Cells Photosynthesis Photosystem Cytochrome f P700 Cytochrome b Cytochrome b6f complex DCMU Cell Biology Plants Radiation Effects Kinetics Microscopy Electron chemistry Spectrophotometry Diuron Cytochromes Oxidation-Reduction |
| Zdroj: | Biochimica et Biophysica Acta (BBA) - Bioenergetics. 253:449-458 |
| ISSN: | 0005-2728 |
| DOI: | 10.1016/0005-2728(71)90048-x |
| Popis: | 1. Light-induced oxidation of cytochrome f in greening bean leaves was first observed after 90 min of illumination. Intense red light was needed to drive the oxidation. At 2 h cytochrome f oxidation was driven by 675 nm monochromatic light, but not by 703 nm light. By 2.5 h the oxidation was driven by 703 nm light and now 675 nm light was less effective. Both the extent and the initial rate of cytochrome f oxidation in 675 nm light were increased more than 10-fold by 3-(3,4-dichlorophenyl)-1,1-dimethylurea (DCMU). These results show that both Photosystems I and II are active at 2.5 h, which correlates with the end of the lag phase in chlorophyll synthesis. Photosystem I is active ahead of Photosystem II. 2. If etiolated leaves are photoconverted and then returned to darkness for at least 2.5 h, Photosystem I is active at the second photoconversion and Photosystem II develops within a period of minutes. In the presence of DCMU, actinic light of 688 nm is more effective than 667 nm or 675 nm light in photooxidizing cytochrome f , even though the absorption maximum of the leaf is at 672 nm. 3. Photosystem II activity, as measured by the ability of 675 nm light to hold cytochrome f mainly in the reduced state was not dependent on the presence of grana or cytochrome b -559. |
| Databáze: | OpenAIRE |
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