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Abstract Detail

Bryological and Lichenological Section/ABLS

Piatkowski, Bryan [1], Kietlinski, Kiel [2], Mansouri, Katayoun [3], Renzaglia, Karen [4].

Apical cell development in the rhizomatous and leafy axes of the enigmatic moss Takakia.

The moss Takakia is a genetically isolated and morphologically distinct genus. Apical organization and growth in this enigmatic bryophyte is a matter of controversy and is the topic of this study. Serial sections of growing aerial shoots and rhizomes of T. ceratophylla and T. lepidozioides were observed with both light and electron microscopy. Serial reconstruction and 3-D modeling of axes were performed to determine the relationship of the apical cell to derivatives and patterns of cell division. All axes examined possess tetrahedral apical cells with three cutting faces. Apical cells segment parallel to each cutting face at 120o angles. This pattern of segmentation is similar to that in liverworts and differs sharply from the tetrahedral (obovoidal) apical cells of most mosses that segment at approximately 137o angles, giving rise to spiraled leaves. In Takakia shoots, irregular phyllids are produced from the three cutting faces, while equal portions of the rhizome originate from each of the three-ranked derivatives. Shoot apical cells are protected by young pyllids and uniseriate axillary mucilage hairs. Similar slime hairs are occasionally found on rhizomatous axes. Although the apical cell is often naked in rhizomes, abundant mucilage is produced by aggregates of stalked 'beaked' mucilage hairs. Plasmodesmata in apical cells are dense when compared to derivatives, which supports the hypothesis that these symplastic connections help coordinate development and differentiation. It can be inferred from these results that apical cell growth similar to Takakia and liverworts such as Haplomitrium was a gametophytic innovation of early land plants.

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1 - Southern Illinois University, Plant Biology, 1125 Lincoln Drive, Life Science II - Room 420, Carbondale, IL, 62901, USA
2 - Southern Illinois University, Plant Biology, 1125 Lincoln Drive, Life Science II - Room 420, Carbondale, IL, 62901, United States
3 - North Carolina State University, Department of Crop Science, 101 Derieux Place, 4405 Williams Hal, Raleigh, NC, 27695, United States
4 - Southern Illinois University, PLANT BIOLOGY DEPARTMENT, MAILCODE 6509, Carbondale, IL, 62901, USA


Presentation Type: Oral Paper:Papers for Sections
Session: 29
Location: Ascot/Riverside Hilton
Date: Tuesday, July 30th, 2013
Time: 2:45 PM
Number: 29007
Abstract ID:833
Candidate for Awards:A. J. Sharp Award

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