Abstract Detail

Novel Approaches to Plant Evolution from Paleontological, Physiological, and Developmental Perspectives

Watkins, James E. [1].

The economy of reproduction in ferns: limitations on fertile-sterile dimorphy.

Organisms must balance between reproduction, growth, and survival. When these processes are in competition, selection may act to drive functional dimorphism. Unlike seed plants, ferns use their foliar surfaces for reproduction and carbon fixation. Across species, ferns exhibit a remarkable gradient of fertile-sterile dimorphy: from the production of highly reduced fertile fronds (holodimorphic) to no reduction (monomorphic) in laminar area between fronds. Here I discuss the physiological impacts of fertile-sterile dimorphy through a series of observational and experimental field manipulations. I combine ecophysiological measurements of photosynthetic rate, water potential, hydraulic conductivity, and shifts in nitrogen content, with experimental d13C labeling and frond removal to evaluate costs of fertile-sterile dimorphy in seven ferns spanning a dimorphism gradient (tropical taxa: Adiantum latifolium, Lomariopsis vestita, and Thelypteris curtii; temperate taxa: Osmundastrum cinnamomeum, Osmunda regalis, Dryopteris marginalis, Onoclea sensibilis, and Polystichum acrostichoides). Fertile sterile dimorphy in ferns appears to come at considerable physiological cost in hemi- and holo-dimorphic species. For this reason, these taxa should combine a series of strategies to help maximize growth and reproduction. Such strategies include establishment in high resource environments, production of long-lived or evergreen leaves, investment in underground or stored resources, and/or shifts in fertile-sterile frond phenology. It is possible that the relative costs of this reproductive system are offset by increased spore dispersal; however, more work needs to be done to quantify potential tradeoffs.

1 - Colgate University, Department Of Botany, 129 Ho Science Center, 13 Oak Drive, Hamilton, NY, 13346-1338, USA

Keywords:
Dimorphy
Reproductive Biology
Ecophysiology
Isotope
Resource Allocation.

Presentation Type: Symposium Presentation
Session: SY11, Novel approaches to plant evolution from paleontological, physiological, and developmental perspectives
Location: 101/Savannah International Trade and Convention Center
Date: Wednesday, August 3rd, 2016
Time: 4:45 PM
Number: SY11008
Abstract ID:122
Candidate for Awards:None