Bryological and Lichenological Section/ABLS
Murray, Rachel V. , Crandall-Stotler, Barbara J. .
SEM Survey of Hydrolyzed Strand Cell Diversity in the Simple Thalloid Liverworts (Jungermanniopsida, subclass Metzgeriidae).
In liverworts, strands of hydroylzed cells that are hypothesized to function in water conduction and/or storage occur only in genera of the Metzgeriidae or simple thalloid group. Characterization of these cells has mostly utilized sectioning techniques, which have not completely resolved the differences observed among strand cell morphologies, particularly as regards pit anatomy and wall architecture. In this study, cell maceration techniques have been used to prepare whole cells for study with SEM and optical microscopy, in combination with SEM study of transverse sections of whole strands. These techniques have allowed us to examine the surface features of both the external and internal walls of the cells for elucidation of pit anatomy and wall architecture and to compare cell shapes and sizes among taxa. Six taxa representing the diversity of strand cell morphologies found in the Pallaviciniaceae Mig. and the basal liverwort Haplomitrium Nees have been studied. The moss Plagiomnium T. J. Kop. was included for comparative purposes. Three different strand cell morphologies were found within the Pallaviciniaceae, namely, 1) thick-walled, perforated, 2) thin-walled, perforated, and 3) thick-walled, unperforated. The strand cells of Haplomitrium differ from those of Pallavicinia Gray only in the deposition of secondary wall material in the latter; wall perforations in both cell types are less than 600 nm in diameter and are formed by plasmodesmatal deterioration. In fact, Symphyogynopsis Grolle in the Pallaviciniaceae has strand cells exactly like those of Haplomitrium. Hattorianthus R. M. Schust. & Inoue is unique among the taxa of the family in depositing thickened walls without plasmodesmatal perforations.
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1 - Southern Illinois University, Department of Plant Biology, 1125 Lincoln Drive, Carbondale, Illinois, 62901-6509, USA
hydrolyzed strand cell
simple thalloid liverwort
Presentation Type: Poster
Location: Salon C, D & E - Gov Ballroom/Hilton
Date: Tuesday, August 16th, 2005
Time: 12:30 PM