Abstract
Bryophytes are widely distributed on the earth and some bryophytes are known to have high desiccation tolerance. In order to find out the mechanism of the tolerance, we have investigated changes in various photosynthetic activities during drying using bryophytes grown under different water environments. We found that PSII fluorescence is quenched and the PSII activity is lost by dehydration, which seems to be important to protect PSII under dry conditions. Here, we will report on the changes in fluorescence Work Integral (WI) due to dehydration, which reflect changes in antenna size of PSII or the rate of QA reduction, in a desiccation-tolerant bryophyte Bryum argenteum. The data show that the moss also has PSIIα and PSIIβ, and the ratio was changed by drying. Relationship among fluorescence quenching, changes in Fv/Fm, and changes in the QA reduction rate will be discussed.
