Photosynthetic capacity of mosses relative to vascular plants

Abstract

The photosynthetic capacity of mosses is generally considered to be much lower than that of most higher vascular plants. Recent evidence indicates that this might be an artefact of the basis for calculating rates of net CO₂ uptake. Maximal photosynthetic rates, under light-saturation and ambient CO₂ levels, were compared in five species of mosses and six species of vascular plants. Although net CO₂ uptake rates of the mosses were substantially lower than those of the vascular plants when rates were expressed on a dry mass basis, this difference disappeared when rates were expressed on a chlorophyll basis. The results indicate that the photosynthetic capacity of mosses is not different from that of higher vascular plants, when measured at light-saturation and ambient CO₂ levels. Thus, photosynthesis in mosses, although ancestral relative to higher vascular plants, has apparently evolved to a similar degree as it has in the more derived higher plants.