They also possess a variety of distinct visual phenotypes that can be used to perform genetic crosses. .
A C-Fern sporophyte is a regular diploid plant. This plant undergoes meiosis on special cells on the underside of leaves, resulting in 1N (haploid) spores. The spores undergo mitosis to produce gametophytes, of which there are two separate genders. One gender is the hermaphrodite, which is relatively large and heart-shaped, and produces both eggs and a small amount of sperm. The other gametophyte gender is a very small, club-shaped male, which produces sperm only. There are no female-only gametophytes.
As mentioned above, there are a number of pure-breeding mutant types that have been developed. One is the Polka Dot gametophyte (cp). In this particular gametophyte, all of its chloroplasts are crammed into one corner of each of the cells instead of being spread out.
The hermaphroditic gametophytes have eggs, just as animals do. When fertilized by sperm from itself, sperm from another hermaphrodite, or sperm from a male, the fertilized egg egg divides to become an embryo, which grows out of the heart-shaped gametophyte. It uses the gametophyte for nourishment until it is big enough to feed itself by phytosynthesis. The new 2N embryo is the new sporophyte generation. The sporophyte can also have normal or mutant characteristics just like the gametophyte.
In our experiment, we analyzed a genetic cross in C-Ferns. We sowed spores from an F1 hybrid sporophyte (Cp/cp), and predicted that the segregation ratio of polka-dot to solid phenotypes would be 1:1 in the gametophyte generation. We then allowed the gametophytes to fertilize, and predicted a 3:1 ratio in the sporophyte generation. The objective of our study was to investigate inheritance of normal phenotype and polka dot phenotype in C-Ferns.
Materials, Methods, and Procedures.
Prior to our lab, petri dishes containing Basic C-Fern Medium were inoculated with spores from an F1 hybrid C-Fern plant.
