Developmental and Structural Section
Seago, James , Soukup, Ales , Votrubova, Olga , Wanntorp, Livia .
Some Unique Structural Features of the Basal Core Eudicot, Gunnera.
We have investigated selected anatomical features of species of the basal core eudicot genus, Gunnera, in order to determine if structures in roots, stems, and leaves reflect the phylogenetic position assigned to it in recent molecular studies. The species include G. killipiana, G. magellanica,and G. perpensa. Root anatomies vary within each species depending upon the size of the roots; large roots usually contain 15-20 arms of xylem and phloem with an endodermis comprised of only Casparian bands. A hypodermis, often with a discontinuous ring of fibers and an exodermis with Casparian bands and suberin lamellae, is present. The stems typically are polystelic; all vascular bundles are surrounded by a uniseriate layer of endodermis, cell walls modified with Casparian bands only; there is either a discontinuous ring of vascular tissue, with primary xylem and phloem surrounded by fibers, or one ring of bundles with a central bundle, each including internal and external fibers within the limits of the endodermis. A thick-walled, multiseriate hypodermis is common in stems, but there is a distinct uniseriate hypodermis in G. perpensa. The petioles of leaves in most species contain an endodermis around each vascular bundle or leaf trace, but the endodermis ceases at the distal end of the petiole prior to entry of the vascular bundle into the leaf lamina which contains no endodermis. There is also a collenchymatous hypodermal zone in petioles.
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1 - State University of New York, Biological Sciences, 129 Snygg Hall, SUNY at Oswego, Oswego, NY, 13126, USA
2 - Charles University, Plant Physiology, Prague, CZ
3 - Swedish Museum of Natural History, Stockholm, Sweden
Presentation Type: Oral Paper:Papers for Sections
Location: Union D/Hyatt
Date: Tuesday, July 10th, 2012
Time: 2:00 PM