POLARIZED PICOSECOND FLUORESCENCE KINETICS IN THYLAKOIDS ORIENTED IN POLYVINYL-ALCOHOL FILM

被引:0
作者
WROBEL, D
NATHER, D
HENDRICH, W
RODER, B
机构
[1] UNIV WROCLAW,INST BIOCHEM,PL-50137 WROCLAW,POLAND
[2] HUMBOLDT UNIV,INST PHYS,O-1086 BERLIN,GERMANY
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D O I
暂无
中图分类号
Q94 [植物学];
学科分类号
071001 ;
摘要
Polarized fluorescence decays in the picosecond time range for thylakoids and isolated photosystem (PS 2) complexes embedded in the stretched polyvinyl (PVA) film were measured after excitation of the samples in the carotenoids (Car) (514.5 nm) and Chl b (476.5 nm) absorption region. The fluorescence kinetics depended on excitation wavelength and the state of radiation polarization. The fluorescence decays of thylakoids and PS 2 in PVA were best fitted to a sum of two exponential lifetime components, although an existence of more than two specimens was indicated. The short lifetimes of about 130-400 ps and long-lived components (3-5 ns) were attributed mainly to emitting PS 2 antenna and light-harvesting Chl a/b complex (LHC), respectively, when embedded in the PVA film. Using the bicomponent model (Lakowicz 1983) for the time-dependent emission anisotropy [r(t)], emission anisotropies (r10 and r20) observed in the absence of rotational motion were determined for PS 2 (r10 = 0.11) and LHC (r20 = 0.37). The differences in lifetimes with differently polarized excitation and emission beams indicated the presence of at least two distinct ways of the energy transfer between Car and Chl a for differently oriented pools of pigments in the thylakoid membrane. This was not found when radiation was absorbed by Chl b (LHC) because of the high rate of the energy transfer between Chl b and Chl a.
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页码:145 / 157
页数:13
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