Antheridiogen activity of Anemia mexicana

Abstract

Gametophytes of two populations of Anemia mexicana Klotzsch exhibited antheridiogen activity. All gametophytes grown as monospore cultures produced organized meristems and only archegonia, although spore size and days from sowing until germination, meristem organization, and archegonia formation varied. In multispore cultures, gametophytes were either antheridiate or archegoniate, indicating that gametophyte interactions are necessary for antheridia formation. When old media extracts from multispore cultures of A. mexicana gametophytes were incorporated into new media, precocious antheridia were formed by A. mexicana and Lygodium japonicum but not by A. phyllitidis, Pteridium aquilinum, or Ceratopteris thalictroides. Few antheridia were initiated by A. mexicana gametophytes under red light, suggesting that antheridiogen could not completely overcome a block to antheridium formation. Spores of A. mexicana, A. phyllitidis, and L. japonicum, but not P. aquilinum and C. thalictroides, germinated in the dark in response to old media extracts incorporated into the basal medium. Thus, antheridiogen activity of A. mexicana is limited to schizaeaceous species of ferns.