Download Density-Dependent Sexual Differentiation in Mutants of Ceratopteris

Density-Dependent Sexual Differentiation in Mutants of Ceratopteris richardii
HEATHER E. JORDAN
Biology Department
College of Natural and Health Sciences
Lake Superior State University
Sault Ste. Marie, MI 49783
Abstract
This study was performed to determine if the types of single gene nuclear mutations carried by various
strains of Ceratopteris richardii significantly alters the percentage of male gametophytes in densitydependent sexual differentiation. In addition to the wild type strain (RNWT1), ten other mutant strains
(abr48, cp, det30, fdr1, her1, him1, rum1, slo1, stl2 and zzz1) were included in the study. Thirty petri
dishes were used to grow gametophytes of each genotype. Each genotype set was subdivided into three
growth density subsets. Each strain was observed over a 10-day period for the number of germinated spores
and the percentage of males within each culture. Results indicate that strains bred for types of chemical
tolerance exhibit similar rates of germination to the wild type (F=1.86) whereas the remaining genotypes
included in the study showed significant differences in these areas. Most strains with altered germination
rates also exhibited significant differences in the percentage of males found in comparison to the wild type
(F=4.01). To date, research has focused primarily on density-dependent sexual differentiation in
populations of infertile mutant strains and sex ratio variations between mutant strains in chemically
supplemented medium. This study suggests that there may be other factors contributing to densitydependent sexual differentiation in C. richardii that are not related to the growth rate of a particular strain.
References Cited:
Scott, R. J., and L. G. Hickok. 1987. Genetic Analysis of Antheridiogen Sensitivity in Ceratopteris
richardii. American Journal of Botany 74: 1872-1877.
Warne, T. R., L. G. Hickok, and R. J. Scott. 1988. Characterization and Genetic Analysis of AntheridiogenInsensitive Mutants in the Fern Ceratopteris. Botanical Journal of the Linnean Society 96: 371-379.