Waite, Mashuri , Sack, Lawren .
Do mosses measure up to vascular plants in functional traits? Interlinkages of photosynthetic light responses and structure and function.
Mosses are an understudied group of plants that can potentially confirm or expand what we know about principles of vascular plant physiology. We hypothesized that moss species differed strongly from vascular plants in physiological and structural traits but would show similar correlations between traits. We expected moss species with higher light-saturated rates of photosynthesis per mass (Amass) to have correspondingly higher light compensation points, saturation irradiances, and leaf nitrogen concentrations (N), and lower leaf mass per area (LMA). We quantified thirty functional, morphological, and physiological traits from cell level, leaf level, and clump level, for ten Hawaiian moss species from forest floor, trunk, and canopy microhabitats. Mosses differed strongly from vascular plants in many functional traits, and showed strong inter-specific variation. Across moss species, leaf cell size in projected area varied 300 fold from 23 to 6890 μm2, LMA varied five fold from 6 to 31 g/m2 , and leaf area index (LAI) varied from 3.9 to 14. Across species, Amass was independent of both light compensation point and saturation irradiance, indicating that for mosses adapted across sun-exposed and shaded habitats, photosynthetic traits may show more diverse combinations than in vascular plants. Also, by constrast with vascular plants, for mosses Amax and N concentration were unrelated to LMA. However, several analagous trait inter-relationships were found for mosses as for vascular plants. Across moss species, clump-level Amass and N were significantly correlated, and both were negatively correlated with clump mass per projected area (CMA), a rapidly measured functional trait. This suggests that in comparing moss and vascular plant leaf traits and trait linkages, the moss clump rather than the moss leaf is the appropriate unit of measurement. Deeper understanding of moss structure-function relationships indicates that despite strong divergence from vascular plants in functional traits, analogous trait coordination underlies ecological differentiation.
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1 - University of Hawaii at Manoa, Botany, 3190 Maile Way, Room 101, Honolulu, Hi, 96822, USA
2 - University of California, Los Angeles, Ecology and Evolutionary Biology, 621 Charles E. Young Drive, Los Angeles, CA, 90095, USA
Presentation Type: Oral Paper:Papers for Topics
Date: Monday, July 28th, 2008
Time: 4:45 PM