MORPHOGENESIS OF GAMETOPHYTES OF FOUR MEXICAN SPECIES OF THE FAMILY THELYPTERIDACEAE

Background: Although there have been studies on the sexual phase of some species of Thelypteridaceae, none have included germination types and prothallial development. Question: Is there variation in the type of germination and prothallial development in the gametophytes of four species in the family Thelypteridaceae? Study species: Four species of the family Thelypteridaceae: Meniscium falcatum, Goniopteris mollis, Goniopteris liebmannii, and Goniopteris minor of the states of Chiapas, Oaxaca, and Tabasco. Methods: Spores were collected, sown in Petri dishes with Thompson culture medium, stored in transparent plastic bags, and placed in a plant growth chamber. The various stages of gametophyte development were fixed in FAA with 0.8 % sucrose, dehydrated in gradual alcohols, critical point dried, mounted on stubs, and coated with gold. The photomicrographs were obtained using a scanning electron microscope (SEM) Model Jeol JSM5310-LV. Results: The spores are monolete and perinate. Germination is of the Vittoria type, and prothallial development of the Aspidium type. Adult gametophytes are cordiform-spatulate, with numerous glandular, simple and single-celled hairs, antheridia and archegonia are of the leptosporangiate type. The first sporophyte leaf is bi or trilobate, with free dichotomous venation, with capitate-glandular hairs, simple, unicellular and acicular hairs, and hypostomatic polycytic stomata. Conclusions: The differences observed among the studied species are: spore size, perispore ornamentation, germination and emergence timing of the rhizoids, type and size of hairs, and development time of gametangia and sporophytes.