Abstract
We have studied on desiccation tolerance in a terrestrial Cyanobacterium, Nostoc commune, and got the following results. 1) Structures of PSI and PSII reaction center (RC) complexes and phycobilisomes change so that absorbed light energy is converted to heat. 2) PSI and PSII activities are inactivated in dryness, but small amounts of water are enough for their recovery. 3) PSII RC remains active in dryness in desiccation sensitive cyanobacteria.
Here, we will report changes in photosynthetic systems during desiccation in various mosses grown under different water conditions. 1) The cause of inactivation of PSII is supposed to be due to dissipation of light energy absorbed by PSII. Quenching of PSI fluorescence was not observed. 2) The PSII activity was less sensitive to the decline of the water potential in the cell than in N. commune. 3) The PSI and II RC remained active in dryness in desiccation-sensitive species.
