Life on earth is dependent upon the conversion of light energy to chemical energy by plants. Since 1960, it has been generally accepted that plants contain two photosystems: photosystem I (PSI) and photosystem I1 (PSII), which are intimately and co-operatively involved in the process of light energy transduction and are located in the thylakoid membranes of the chloroplasts. This chapter reviews the ways in which photosystems may interact and examines the possible consequences of such interactions on thylakoid function. Sufficient background information is provided to allow a sensible perspective of photosystem interactions to be developed. To understand the nature and functions of the photochemical apparatus and the potential mechanisms for regulating the photochemical processes, the characteristics of the thylakoid membranes are considered. It is apparent from the preceding discussions that knowledge of the composition and organization of the thylakoid membrane has advanced enormously in recent years and demonstrated the potential for many interactions between intrinsic pigment-containing, macromolecular complexes. However, the physiological significance of such interactions has not been satisfactorily resolved. This is especially true of the interactions between complexes that result in modifications in excitation energy distribution between PSI and PSII.
ASJC Scopus subject areas
- Plant Science