Low temperature enhances photosynthetic down-regulation in French bean (Phaseolus vulgaris L.) plants
| Autor: | Hamlyn G. Jones, Tsonko Tsonev, Violeta Velikova, Paul F. Hyde, Katya Georgieva |
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| Rok vydání: | 2003 |
| Předmět: |
Chlorophyll
Time Factors Photosystem II Plant Science Photosynthesis Acclimatization Fluorescence chemistry.chemical_compound Botany Chlorophyll fluorescence chemistry.chemical_classification Phaseolus biology food and beverages Pigments Biological Original Articles biology.organism_classification Adaptation Physiological Cold Temperature chemistry Xanthophyll Sunlight Photorespiration |
| Zdroj: | Annals of botany. 91(3) |
| ISSN: | 0305-7364 |
| Popis: | The mechanisms of photosynthetic adaptation to different combinations of temperature and irradiance during growth, and especially the consequences of exposure to high light (2000 micro mol m(-2) s(-1) PPFD) for 5 min, simulating natural sunflecks, was studied in bean plants (Phaseolus vulgaris L.). A protocol using only short (3 min) dark pre-treatment was introduced to maximize the amount of replication possible in studies of chlorophyll fluorescence. High light at low temperature (10 degrees C) significantly down-regulated photosynthetic electron transport capacity [as measured by the efficiency of photosystem II (PSII)], with the protective acclimation allowing the simulated sunflecks to be used more effectively for photosynthesis by plants grown in low light. The greater energy dissipation by thermal processes (lower F(v)'/F(m)' ratio) at low temperature was related to increased xanthophyll de-epoxidation and to the fact that photosynthetic carbon fixation was more limiting at low than at high temperatures. A key objective was to investigate the role of photorespiration in acclimation to irradiance and temperature by comparing the effect of normal (21 kPa) and low (1.5 kPa) O(2) concentrations. Low [O(2)] decreased F(v)/F(m) and the efficiency of PSII (Phi(PSII)), related to greater PSII down-regulation in cold pre-treated plants, but minimized further inhibition by the mild 'sunfleck' treatment used. Results support the hypothesis that photorespiration provides a 'safety-valve' for excess energy. |
| Databáze: | OpenAIRE |
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