Schizaea pusilla is a rare fern that, in North America, inhabits acid bogs of New Jersey, Nova Scotia, and Newfoundland. The gametophytes are initially negatively phototropic (grow away from the light), but become positively phototropic (grow toward the light) at a later stage in development. For positively phototropic plants, the cytoskeleton provides orientation and stability for growth and development, but the cytoskeleton in this negatively phototropic fern is uncharacterized. In this study, we characterized the cytoskeletal elements of Schizaea pusilla gametophytes in the early negatively phototropic stage using immunofluorescence and immunoblotting techniques. We found that cytoskeletal proteins in the negatively phototropic gametophytes of Schizaea pusilla are present and similar in molecular weight to that of most other positively phototropic higher plant species. In addition, we have characterized the arrangement of cytoskeletal elements during the negatively phototropic stage.

Key words: cytoskeleton, gametophyte, negative phototropism, Schizaea pusilla