Ferns

Cody Olson

Fern: Sex Expression and Gametophytic Density

INTRODUCTION:

The C-fern is a type of plant that is found in tropical and subtropical climates and can also be diploid or haploid. The haploid C-fern will either develop as a male or into a hermaphrodite and when there are no males present the hermaphrodite ferns will secrete antheridogen into the surrounding areas, which will cause spores that are germinating later to turn into males. The C-fern is a great study plant because it develops at a very fast pace and has both diploid and haploid cells which can be studied separately. We designed an experiment with the C-fern because we were trying to see if there was a correlation between the density of spores in an area and how many of each sex we would find. Does the density of the population contribute to more or less males/hermaphrodites?

METHODS:

For this experiment we took six different petri dishes and labeled them each a different code, A-F, and the date we started. In each of the dishes we put different densities of spores that were suspended in a water solution. For the A dish we had spores that only had 12 drops of water in it. B dish had spores with 18 drops of water, C had spores with 24 drops of water, D had spores with 30 drops of water, E had spores with 36 drops of water and F had spores with 42 drops of water. After the spores were in the dishes we used a spore spreader to spread the spores all around the dish. The dishes were then set underneath lights, next to a window, inside of a culture dome.