NOTIS, CHRISTINE. Department of Botany, Iowa State University, Ames, IA 50011. - Sperm longevity and swimming distance in ferns.
The goal of this study is to determine the maximum longevity and
swimming distance of fern sperm in liquid media of differing pH and
solute concentration. This information is relevant to determining
gametophyte population densities necessary for intergametophytic
crossing. Species used in the study included Lygodium japonicum,
Macrothelypteris torressiana, Pteridium aquilinum and Asplenium
pinnatifidum. For determinations of longevity, culture-grown male
or bisexual gametophytes were submersed in the test solution in a
microscope depression slide. After five minutes the gametophytes were
removed leaving only the sperm that had been released into the medium.
The solution was then checked every 15 minutes to determine whether
sperm remained active. Results indicate that sperm are capable of
swimming for over two hours. Longevity decreased with increasing
acidity for the species tested. Additional species are being tested
and swimming distances are being calculated.
Key words: cross-fertilization, fern, neighborhood size, sperm