A moss "canopy" - Small-scale differences in microclimate and physiological traits in Tortula ruralis
2007
Zotz, G. | Kahler, H.
We studied vertical changes in light regime and water content (WC) in combination with vertical gradients in several physiological response variables, i.e. net CO₂ uptake, chlorophyll content and nitrogen content in the moss species, Tortula ruralis. The rate of light attenuation within the moss turf, which was determined with a custom-made optical microprobe system, was strongly dependent on plant WC. Curling movements of the upper leaves associated with the beginning desiccation of the uppermost parts of a turf allowed increased penetration of light to greater depth with decreasing WC. The capacity to fix carbon declined steeply with depth: below ca. 9mm no net CO₂ uptake occurred, even when removing the shading parts above. The potential rates of photosynthesis in different depths were highly correlated with chlorophyll content, but not nitrogen content.
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