THE ROLE OF CHLOROPHYLL B IN THE PHOTOPROTECTION OF PHOTOSYSTEM I AND II USING CHLOROPHYLL B LESS MUTANTS

摘要

During photosynthesis light energy is absorbed by pigments, such as chlorophyll (Chl) a, Chl b and carotenoids and transferred to the reaction centers. The main function of Chl b is to gather light energy together with Chl a and carotenoids. Chl b also contribute to assembly of light harvesting complexes (LHCs), so for instance Chl b-deficient barley mutants lack many LHC proteins bound both to PS I and PS II (Bossmann et al 1997). In other hand Chl b bound to chlorophyll a/b-binding apoproteins andenhance their import into chloroplast and assembly of LHCs (Eggink et al 2001). Hence lacking of Chl b resulted in the reduction of the antenna size and the destabilization of PS II (Jansson 1994). Chl a/b ratio is high in highlight growth conditions than in low-light growth conditions, which is accompanied by large size of antenna complexes in low-light growth conditions indicating that the regulation of Chl b synthesis is important for understanding the mechanism of adaptation of plants to various light intensity and role of the Chl b in photoprotection.