Photosynthetic and Respiratory Activity in Anacystis nidulans Adapted to Osmotic Stress.

Anacystis nidulans cultures growing photoautotrophically in a minimal medium were exposed to different concentrations of NaCl, up to 0.4 molar. Initially, a marked decrease in photosynthetic activity took place, which was in direct relation to the salt concentration and which was not associated with a change in endogenous respiratory activity. After a period of exposure to salinity, a process of adaptation became apparent, being manifested in a partial reversal of the decline in photosynthesis and a marked increase in endogenous respiration.