Schwendemann, Andrew B. , Taylor, Thomas N. , Taylor, Edith L. .
Fossil Root Nodules Containing Arbuscular Mycorrhizal Fungi from the Triassic of Antarctica.
Arbuscular mycorrhizal (AM) fungi play a critical role in the life of plants. These organisms improve plant performance in drought and stress conditions through the uptake of nutrients and minerals. Symbiotic relationships between AM fungi and plants occur in over 80% of extant land plants and can be documented back to the Devonian. The earliest fossil evidence of AM fungi in true roots occurs in Antarcticycas from the Triassic of Antarctica, although this may be due primarily to preservational biases against these fragile and ephemeral structures. In some families, plants form root nodules that are later colonized by AM fungi. In the Podocarpaceae, root nodules develop from the pericyle near a protoxylem pole. Vascuar tissue extends into the center of the nodule and remains surrounded by a layer of the endodermis. Root nodules of this type are found in Notophytum krauselii, a probable podocarp from the Triassic of Antarctica. These permineralized fossils represent the earliest known occurrence of root nodules in the fossil record and coincide with early fossils of the Podocarpaceae, suggesting that the ability to form nodules evolved far earlier than previously suggested.
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1 - University of Kansas, Department of Ecology & Evolutionary Biology, Natural History Museum and Biodiversity Research Center, 1200 Sunnyside Avenue, Lawrence, Kansas, 66045-7534, USA
Presentation Type: Oral Paper:Papers for Sections
Date: Monday, July 28th, 2008
Time: 9:45 AM