tailieunhanh - Báo cáo khoa học: Photosynthetic acclimation: State transitions and adjustment of photosystem stoichiometry – functional relationships between short-term and long-term light quality acclimation in plants

In dense plant populations, individuals shade each other resulting in a low-light habitat that is enriched in far-red light. This light quality gradient decreases the efficiency of the photosynthetic light reaction as a result of imbalanced excitation of the two photosystems. Plants counteract such con-ditions by performing acclimation reactions. | MINIREVIEW Photosynthetic acclimation State transitions and adjustment of photosystem stoichiometry - functional relationships between short-term and long-term light quality acclimation in plants Lars Dietzel Katharina Brautigam and Thomas Pfannschmidt Junior Research Group Department for Plant Physiology Institute of GeneralBotany and Plant Physiology Friedrich-Schiller-University Jena Germany Keywords higher plants light quality long-term response photosynthesis photosynthetic acclimation photosystem stoichiometry redox control seed production state transitions thylakoid kinases Correspondence T. Pfannschmidt Junior Research Group Department for Plant Physiology Institute of GeneralBotany and Plant Physiology Friedrich-Schiller-University Jena Dornburger Str. 159 07743 Jena Germany Fax 49 3641 949232 Tel 49 3641 949236 E-mail Received 21 September 2007 revised 19 December 2007 accepted 2 January 2008 doi In dense plant populations individuals shade each other resulting in a low-light habitat that is enriched in far-red light. This light quality gradient decreases the efficiency of the photosynthetic light reaction as a result of imbalanced excitation of the two photosystems. Plants counteract such conditions by performing acclimation reactions. Two major mechanisms are known to assure efficient photosynthesis state transitions which act on a short-term timescale and a long-term response which enables the plant to re-adjust photosystem stoichiometry in favour of the rate-limiting photosystem. Both processes start with the perception of the imbalanced photosystem excitation via reduction oxidation redox signals from the photosynthetic electron transport chain. Recent data in Arabidopsis indicate that initialization of the molecular processes in both cases involve the activity of the thylakoid membrane-associated kinase STN7. Thus redox-controlled phosphorylation events may not only adjust photosystem