ABSTRACT
Aquatic bryophytes are ecologically important in river phytobenthos, especially in mountain streams, despite the adverse environmental conditions. Other hostile aquatic habitats, such as deep lakes with dramatic light starvation, are also successfully inhabited by bryophytes. Some future trends in the investigation of the ecophysiology of pigments in aquatic bryophytes, such as the functioning of the xanthophyll cycle and the use of chlorophyll fluorescence as a vitality index, are outlined. The core complex of PSII contains only chl-a and beta-carotene as photosynthetic pigments. The close correlation that has been reported in aquatic bryophytes between the spectrophotometrically-determined concentrations of chl-b and phaeophytin-a probably derives from the characteristic presence of both pigments in PSII. The genetic influence on pigment composition is clearly observed in the colour of the different species, which is sometimes used as a taxonomical tool. In higher plants, pigment variations are diagnostic symptoms for several nutrient deficiencies, toxicities or antagonisms.
