Photoinhibition of Photosystem 1

Till recently the term photoinhibition (PI) has been related to PS2 part of photosynthetic electron transport chain, in spite of some publications showing that PS1 can also be inhibited at definite conditions. At chilling temperature and low light intensity PS1 is selectively inhibited while PS2 remains practically unchanged. This review describes the nature of PS1 PI; the differences between PS1 and PS2 PI; PI of PS1 and chilling stress of photosynthesis; mechanisms of PS1 PI and their targets; reactive oxygen species as the primary cause of photoinhibitory injury of PS1; degradation of PsaB and PsaA gene products – the site of PS1 PI. In the conclusion some questions were put on to be answered in the near future.