Skelton, Chanda , Farrar, Donald .
The effect of culture conditions on sex ratios in gametophyte populations of Pteridium aquilinum.
Previous studies on fern gametophytes have primarily been conducted within the laboratory under controlled laboratory conditions. The use of laboratory cultures to predict breeding systems in nature raises the question of whether or not conclusions drawn from these studies accurately reflect what is occurring in nature. Some previous studies have found differences in sex ratios between laboratory and field populations. We speculated that these differences were not necessarily a result of laboratory culture conditions, but instead result from the way in which spores are typically sown onto culture media. Laboratory cultures are generally inoculated onto culture media in a single sowing of spores, whereas field populations may receive several successive innoculations of spores over the duration of spore release from source sporophytes. In order to replicate the multiple spore introductions of natural populations, we added spores to our laboratory cultures over a period of ten days, then determined sex ratios of the resulting populations. Results indicate that staggering the application of the spores onto the medium results in elevated male:female ratios that more accurately reflects the sex ratios of field populations. Other factors such as soil vs. agar medium and heterogeneous vs. flat media surfaces also increased the number of male gametophytes. Our results indicate that changes in standard laboratory protocol may be required to produce culture populations that accurately reflect sex ratios found in nature.
Log in to add this item to your schedule
1 - Iowa State University, Ecology, Evolution, Organismal Biology, 253 Bessey Hall, Ames, IA, 50011, USA
2 - Iowa State University, Department of Ecology, Evolution & Organismal Biology, 253 Bessey Hall, Ames, Iowa, 50011-1020, USA
fern gametophyte sexuality
Presentation Type: Oral Paper:Papers for Sections
Location: Lake Michigan/Hilton
Date: Monday, July 9th, 2007
Time: 1:45 PM