FARRAR, DONALD*, SUSAN ALDWORTH, CHARLES BUTTERWORTH, DENISE FRIEDRICK, GLENN FUCHS, ANNA GARDNER, ROSARIA HEALY, DEBORAH LEWIS, CATHY MABRY, CHRISTINE MINOR, LARISSA MOTTL, AND JAMES WATKINS. Department of Botany, Iowa State University, Ames, IA 50011. - How long can fern sperm swim?
Although observation of swimming sperm has become routine in
classrooms, experimental determination of the duration of individual
sperm activity has not been reported. By immersing male gametophytes
into liquid media, allowing sperm release, then withdrawing the
gametophytes, we have conducted simple tests of the duration of sperm
motility for a number of species, genera, and families of
leptospsorangiate ferns. Sperm activity up to two hours after release
is not unusual. Further experiments test efficacy of sperm in
fertilization with increasing age. Results have application to
estimation of neighborhood size in still or flowing films of water
that permit intergametophytic sperm transfer.
Key words: fern gametophyte, fern reproduction, fern sperm, neighborhood size