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Developmental and Structural Section

Blackwell, Andrew J. [1], Gates, Hilarie D. [2], Renzaglia, Karen S. [1].

Reconstruction of the sperm cells of two bryophytes: from the transmission electron microscope through three-dimensional digital models.

Sperm cells are the most complicated cells produced by land plants. Because transmission electron microscope (TEM) micrographs show only a very thin section of the cell, large numbers of micrographic images are needed to visualize sperm in three-dimension. Hand-drawn reconstructions of plant sperm cells have made detailed micrographic data easier to interpret. This project carries on the tradition of converting complex images taken on the TEM into three-dimensional models, but differs from previous studies in that the reconstructions are computer-drawn. Approximately two hundred images were analyzed for each of two bryophytes; Phaeoceros hirticalyx, a hornwort and Haplomitrium mnioides, a liverwort. From this two-dimensional information, three-dimensional computer images were produced and colorized. The sperm cell of Phaeoceros coils 1.5 revolutions and contains two flagella inserted into the cell anterior by short basal bodies that lack stellate patterns. A spline that contains a maximum of 12 microtubules provides a structural framework that anchors the following organelles from front to back: an anterior mitochondrion, a long cylindrical nucleus, an inconspicuous posterior mitochondrion, and a plastid containing one large starch grain. Although similar in length and diameter, the sperm cells of Haplomitrium are much broader than those of Phaeoceros. The two flagella and dimorphic basal bodies are staggered in insertion into the cell anterior. The spline is nearly 100 microtubules in maximum width and it overlies an anterior mitochondrion, a broad cylindrical nucleus, two posterior mitochondria and two starch-filled plastids. Colorized three-dimensional models of these two cells facilitate comparisons between similar structures and highlight the elaborate architecture of these cells.

1 - Southern Illinois University, Department of Plant Biology, 1125 Lincoln Drive, Carbondale, Illinois, 62901-6509, USA
2 - Southern Illinois University, Carbondale, Integrated Microscopy and Graphics Expertice (IMAGE) Center, 750 Communications Drive, Carbondale, Illinois, 62901-4402, USA

reproductive morphology
sperm cell

Presentation Type: Poster
Session: 32-10
Location: Special Event Center (Cliff Lodge)
Date: Tuesday, August 3rd, 2004
Time: 12:30 PM
Abstract ID:505

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