Are bryophytes shade plants? Photosynthetic light responses and proportions of chlorophyll a, chlorophyll b and total carotenoids

� Background and Aims Data are presented from 39 species of mosses and 16 liverworts for ratios of chlorophylls and total carotenoids, and light saturation of photosynthetic electron flow or photosynthetic CO2 uptake, in relation to the postulate that bryophyte cells in general show shade-plant characteristics. � Methods Pigment concentrations were measured by spectrophotometer in 80 % acetone extracts. Light-saturation curves were constructed by (modulated) chlorophyll florescence and for some species by infra-red gas analysis. � Key Results The pigment measurements were widely variable but broadly in line with the findings of previous authors. Median values (mosses/liverworts) were: total chlorophyll, 1� 64/3� 76 mg g � 1 ; chlorophyll a : b ,2 � 29/1� 99; chlorophylls :carotenoids, 4� 74/6� 75). The PPFDvalues at 95 % saturation (estimated fromfitted curves) also ranged widely,butwerealmostall