Abstract
At the last meeting, we reported that hypertonic treatments of a terrestrial, highly drought-tolerant cyanobacterium, Nostoc commune, can mimic drying processes in this cyanobacterium. We also reported that N. commune actively (not passively) deactivates photosynthetic systems at an early stage of drying.
In order to further study how N. commune changes photochemical reaction center complexes in various stages of desiccation, we observed the effects of light and high temperatures under various osmotic conditions. In N. commune, the PSII activity was not decreased by light, and its temperature sensitivity shifted to a higher value by 5oC. On the contrary, in Synechocystis sp. PCC6803, which has no desiccation tolerance, the PSII activity was further inhibited by light, and the temperature sensitivity was not changed under hypertonic conditions.
We will also discuss on effects of liquid cultivation on drying stress in various strains of N. commune.
