Watkins, James , Testo, Weston , Sennett, Aurelian , Oliver, Melvin J. , Pruitt, Nancy .
The ecophysiology of hemiepiphytism in the ferns: lessons from Lomariopsis vestita .
Hemiepiphytism in ferns is rare, yet emerging data suggest that this life form may have played an important role in the evolution of fern epiphytes. There is evidence from both the Elaphoglossaceae and the Davalliaceae that epiphytism arose from hemiepiphytic progenitors. The goal of this work was to examine several ecological and ecophysiological aspects of the hemiepiphytic fern Lomariopsis vestita to shed light on the functional ecology of fern hemiepiphytes. Lomariopsis vestita is one of the few primary fern hemiepiphytes and invariably begins its life as epiphytic gametophytes on understory trees. Following sporophyte recruitment, individuals produce a few small linear to trident leaves and invest heavily in root production. Fine roots grow down the trunk and contact the mineral soil. Contact with the soil induces a heteroblastic leaf series that shifts into the mature sporophyte in a few months. We assessed changes in both desiccation tolerance and nitrogen relations across this developmental series from gametophytes to young epiphytic sporophytes to young terrestrially connected sporophytes and small mature terrestrially connected sporophytes. As epiphytes, both gametophytes and young sporophytes yielded 15N natural abundance signatures indicative of atmospheric uptake while soil-connected sporophytes reflected more enriched signatures expected from mineral soil. We also discovered that both epiphytic gametophytes and epiphytic sporophytes were markedly desiccation tolerant, whereas once roots contacted the soil, this character was lost and sporophytes became desiccation sensitive. Our data indicate that hemiepiphytism in ferns is a complex process that involves metabolic shifts at many fundamental levels. Future work will focus on combining molecular and ecophysiological data to develop a better picture of metabolomic shifts across life forms and habitats.
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1 - Colgate University, Department Of Botany, 129 Ho Science Center, 13 Oak Drive, Hamilton, NY, 13346-1338, USA
2 - Colgate University, Box Z 5647, Hamilton, NY, 13346, USA
3 - University of Missouri, Columbia, Plant Sciences, 205 Curtis Hall, Columbia, MO, 65211, United States
4 - Colgate University, Department Of Botany, 13 Oak Drive, Hamilton, NY, 13346, United States
Presentation Type: Oral Paper:Papers for Sections
Location: Union E/Hyatt
Date: Monday, July 9th, 2012
Time: 8:30 AM