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.