Bryological and Lichenological Section/ABLS
Mansouri, Katayoun .
Immunocytological analysis of callose in cell walls across generative apices and tissues of liverworts and mosses.
Geometrically distinct apical cells (lenticular, tetrahedral, hemidiscoid and cuneate) in gametophytes of bryophytes determine growth habits of these plants. All four types of apical cells are present in the morphologically diverse liverworts, while in mosses tetrahedral (technically obovoid) cells predominate. Leafy and thalloid growth forms of both mosses and liverworts are correlated with these geometries in a way that each apical derivative (merophyte) gives rise to an organ: leaf, leaf-like structure, portion of the stem and thallus. Immediate and successive divisions of the apical cell result in an arrangement of organs that follows the outline of the cutting faces of the apical cell. For example, tetrahedral cells in liverworts have three cutting faces from which three rows of leaves originate. Apical cells and derivatives are symplastically connected via plasmodesmata (PD). In Bazzania trilobata immediate derivative cell walls compare to apical cell walls lose plasmodesmata and it is possible that they are occluded with callose (1,3-β-glucan). Plasmodesmata density in apical cell walls of Haplomitrium mnioides decreases in derivatives, however there is no change in total numbers and therefore no loss of PD. In this study apical meristems (apical cell and derivatives) of the liverworts Haplomitrium mnioides, Metzgeria conjugata and Bazzania trilobata and the two species of Takakia as well as Physcomitrella patens were examined for callose using immunogold labeling with a monoclonal anti-callose antibody. The ends of plasmodesmata in bryophytes label for callose as in tracheophytes.
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1 - Southern Illinois University Carbondale, Plant Biology, Life Science II 459, Carbondale, IL, 62901, USA
Presentation Type: Oral Paper:Papers for Sections
Location: 554A/Convention Center
Date: Tuesday, August 3rd, 2010
Time: 9:30 AM