Date of Award
Bachelor of Science
light, photosynthesis, canopies, angles, rough
In open habitats, Sphagnum grows with a dense architecture to retain water; mosses adapted to survive in shade persist in looser canopies. It is unknown if there is a physiological advantage of such rough canopies in the shade, but they may have enhanced photosynthesis at low light angles as would occur during spring or fall. It was hypothesized that the rough canopies would have enhanced rates of photosynthesis at lower angles. To test this, a photosynthesis system interfaced with a custom chamber was used to generate light response curves. Preliminary results of the study found no difference in photosynthesis with light normal to the canopy, compared with light at 45° in naturally formed core samples-- a leaf surface would decline with the cosine of the angle. Experimental data using rough and smooth canopies showed no significant difference in photosynthesis between rough and smooth canopies (p=0.09) at all angles tested (90°, 45°, and 22.5°). Among angles, photosynthesis significantly decreased with the angle of incident light, but outperformed predicted declines. Other factors that influence light transmission within the canopy independent of roughness may account for these results.
Ward, Eric Matthew, "The Effects of Canopy Structure on Photosynthesis in Sphagnum Mosses" (2015). Honors Theses and Student Projects. 401.