Bryological and Lichenological Section/ABLS
Merced-Alejandro, Amelia , Renzaglia, Karen S. .
Ultrastructure of pseudostomata in Sphagnum angustifolium.
The origin and diversification of stomata remain among the most significant evolutionary problems in land plants. Stomata are present across all land plants except liverworts. The most widely accepted phylogeny of early land plants place the liverworts as the earliest divergent clade, making a single origin of stomata after this divergence the most parsimonious interpretation. The problem with is that there are no true stomata in the earliest divergent mosses. The so-called pseudostomata of Sphagnum consist of two epidermal cells that do not form pores and are not involved in gas exchange but function in drying of the capsule. Pseudostomata are most likely not functionally homologous to stomata in other mosses but they may be derived from stomata or vice versa, i.e., they are structural homologs. Cell wall ultrastructure of pseudostomata in open and closed capsules of Sphagnum angustifolium were examined using TEM and light microscopy. Thickness and layering of the cell walls and inner anatomy of the capsule near pseudostomata are described. These information is then compare to data publish for true stomata of Funaria. If stomata are homologous to pseudostomata then a remnant of common ancestry is likely evident in the ultrastructure and morphology of guard cell.
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1 - Southern Illinois University, Department of Plant Biology, 1125 Lincoln Drive, Carbondale, IL, 62901-6509, USA
2 - Southern Illinois University, Department of Plant Biology, 1125 Lincoln Drive, Carbondale, Illinois, 62901-6509, USA
Presentation Type: Oral Paper:Papers for Sections
Location: 554A/Convention Center
Date: Tuesday, August 3rd, 2010
Time: 11:15 AM