Cell surface topography duringMarsilea spermiogenesis: Flagellar reorientation and membrane particle arrays

Abstract

Changes in the cell surface during spermiogenesis in the fern,Marsilea, have been investigated by freeze-fracture. Early in development 150 or more flagella appear on the surface of the spermatid cell. As they grow in length, they change orientation in relation to the spermatid cell surface and to each other. While the flagella are growing, a band of membrane particles surrounds each flagellum at the transition zone. These particles disappear near the end of development and are not seen in mature sperm. Other particles are associated with the plasma membrane during development. One set of particles is found early in spermiogenesis in hexagonal arrays. At the end of spermiogenesis, these are no longer observed, but clusters of particles, with no particular order, appear around the flagellar bases, following the line of the flagellar band.