Poster: Vegetative development

Abs # 317: Auxins and Ceratopteris richardii gametophyte development

Presenter:	Fisher, Roxanne H, rfisher@chatham.edu
Authors	Fisher, Roxanne H (A)   Gregorich, Michele  (A)
Affiliations:	(A): Department of Biology, Chatham College

Higher plants have finely tuned developmental mechanisms that result from millions of years of evolution. Many of these mechanisms exist in lower plants and are conserved in higher plants. Ferns provide a link between the lower plants and the seed plants; studying the growth and development of ferns may give us insight into the evolution of developmental mechanisms. Auxins affect many aspects of plant growth and development: apical dominance, tropisms, pattern formation, and cell elongation. We are studying the effects of auxins and antiauxins on the growth and development of Ceratopteris richardii gametophytes. Our experiments show that the synthetic auxins NAA and 2,4,5-T, and the anti-auxin PCIB have substantial effects on gametophyte development. NAA can induce apical dominance in gametophytes while streamlining the typical hermaphrodite body form by repressing activation of the lateral meristem. 2,4,5-T causes horizontal elongation while generating growth from behind the gametophyte. Gametophytes grown on medium containing PCIB are shorter and wider than control gametophytes, and activate their lateral meristems to attain the typical hermaphrodite form. We exposed gametophytes to a temporal progression of auxin and control media which allowed us to establish a developmental timeline for auxin action. This work increases our knowledge about auxin action in lower plants and will add to our understanding of the evolution of developmental mechanisms in lower and higher plants.