| Popis: |
The unicellular green alga Scenedesmus obliquus adapts to different irradiances and wavelengths of light by altering the molecular organization of the photosynthetic apparatus. Regulation occurs on the level of pigment-accumulation, assembly of pigment-protein complexes and gene-expression. Action spectroscopy revealed the involvement of at least two photoreceptor-systems regulating adaptation antagonistically with markedly different thresholds (Thielmann et al., 1991; Thielmann and Galland, 1991). One of them was a BL-(flavin-type-) receptor, which mediates weak-light adaptation, resulting in increased Chl, LHC II (Humbeck et al., 1988; Senger and Bauer, 1987) and accumulation of cab-mRNA (Hermsmeier et al., 1991); the other one was a VL/RL-receptor with action peaks at 404 and 650 nm, inducing high-irradiance responses indicated by decreased amounts of Chl, LHC II, LHCP and cab-mRNA (Hermsmeier et al., 1991). |
