Inactivation of photosystems I and II in response to osmotic stress in Synechococcus. Contribution of water channels

Suleyman I. Allakhverdiev, Atsushi Sakamoto, Yoshitaka Nishiyama, Norio Murata

Research output: Contribution to journalArticle

115 Citations (Scopus)


The effects of osmotic stress due to sorbitol on the photosynthetic machinery were investigated in the cyanobacterium Synechococcus R-2. Incubation of cells in 1.0 M sorbitol inactivated photosystems I and II and decreased the intracellular solute space by 50%. These effects of sorbitol were reversible: Photosynthetic activity and cytoplasmic volume returned to the original values after removal of the osmotic stress. A blocker of water channels prevented the osmotic-stress-induced inactivation and shrinkage of the intracellular space. It also prevented the recovery of photosynthetic activity and cytoplasmic volume when applied just before release from osmotic stress. Inhibition of protein synthesis by lincomycin had no significant effects on the inactivation and recovery processes, an observation that suggests that protein synthesis was not involved in these processes. Our results suggest that osmotic stress decreased the amount of water in the cytoplasm via the efflux of water through water channels (aquaporins), with resultant increases in intracellular concentrations of ions and a decrease in photosynthetic activity.

Original languageEnglish
Pages (from-to)1201-1208
Number of pages8
JournalPlant physiology
Issue number4
Publication statusPublished - Apr 2000


ASJC Scopus subject areas

  • Physiology
  • Genetics
  • Plant Science

Cite this