FUNCTIONS OF PHYCOBILISOMES IN DELIVERY OF EXCITATION ENERGY TO PHOTOSYSTEMS I AND II AND CAROTENOID-INDUCED PROTECTION OF PHYCOBILISOMES AGAINST PHOTOBLEACHING

摘要

The role of the light-harvesting antenna in cyanobacteria and red algae is performed by pliycobilisom.es (PBS), generally assuming to be employed as the external antenna of photosystem II (PSII) (Stadnichuk 1991, Sidler 1994). However, it has been demonstrated that the excitation energy from PBS can also be transferred to photosystem I (PSI) (Rakhimberdieva et al 2001 and ref. there). PBS absorb the most part of photosynthetically active radiation and no quenchers of the excess light energy have beenfound in isolated PBS (Suter et al 1984). The intriguing questions of PBS function are: (1) shares of PBS-absorbed energy delivered to each photosystem; (2) participation of PSII in energy migration from PBS to PSI; (3) possible presence of PBS detached from antenna chlorophylls; (4) quenching of the excess excitation energy absorbed by PBS.