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Abstract Detail


Bryological and Lichenological Section/ABLS

Piatkowski, Bryan [1], Bader, Geoffrey [1], Wallace, Anne [1], Kellam, Laura [1], Branning, Jessica [1], Corbicz, Matthew [1], Poli, DorothyBelle [1].

Examining Polar AuxinTransport Evolution in Bryophyte Gametophytes.

Most hormone transport is through vascular tissue, but plants can transport auxin (IAA) uni-directionally through specialized cells in a process called polar auxin transport (PAT). Bryophytes have been shown to exhibit similar auxin-controlled responses as vascular plants. Since bryophytes are intermediate between Chlorophyta and vascular plants, it is optimal to use them when studying physiological evolution. Hormone metabolism was measured using 3H-IAA. Data collected from the liverwort gametophytes, Riccia fluitans, suggest that simple diffusion is utilized for the transport of auxin into the cell. Gametophytes of hornworts (Phaeoceros laevis, Anthoceros punctatus and A.agrestis) and of the moss (Rhizomnium sp.) tested displayed facilitated diffusion influx. All species displayed facilitated diffusion as the method of auxin efflux. Moreover, the more complex Rhizomnium showed sensitivity to the influx inhibitor 1-naphthoxyacetic acid (NOA) and the efflux inhibitor 1-N-naphthylphthalamic acid (NPA), effective inhibitors on protein carriers in vascular plants. PAT assays were used to determined directionality of auxin transport in the moss Dicranum scoparium gametophyte which suggests a non-polar orientation of auxin transport protein carriers. The results suggest that bryophyte gametophytes contain protein carriers similar to those used in PAT in vascular plants but that the process may not be unidirectional or specialized yet.

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1 - Roanoke College, Biology, 221 College Lane, Salem, VA, 24153, USA

Keywords:
Bryophytes
gametophytes
auxin
transport proteins
Evolution.

Presentation Type: Oral Paper:Papers for Sections
Session: 14
Location: Morrow/Hyatt
Date: Monday, July 9th, 2012
Time: 2:30 PM
Number: 14005
Abstract ID:502


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