Feather mosses serve as important regulatory organisms for many ecological processes in boreal forests. They are generally considered to be ectohydric species, transporting water on the surface of the plant. But is this really so? Sokołowska et al. investigate their stem tissue traits and ability to transport solutes via food-conducting cells internally under modified environmental conditions.
They find that food-conducting cells that have a major role in determining internal conduction in the pleurocarpous mosses Pleurozium schreberi and Hylocomium splendens. Both P. schreberi and H. splendens are able to absorb solutes from the stem surface and transport them horizontally towards the stem interior and vertically towards the apex. These findings are the first direct evidence of internal (endohydric) transport in feather mosses and contradict the general assumption that these mosses are exclusively ectohydric.
In addtition, the central strand of Pleurozium schreberi stems consists of hydroids, water conuducting cells, that contribute to effective internal long-distance transport, in particular during low air humidity conditions. The authors infer that these mosses should not be regarded exclusively as ectohydric species.