Bryological and Lichenological Section/ABLS
Zhang, Li , Crandall-Stotler, Barbara J. , Stotler, Raymond E. .
The occurrence of tubers in Noteroclada confluens Taylor ex Hook. & Wilson.
Noteroclada confluens is a monotypic, simple thalloid liverwort that grows in moist, montane habitats from Mexico to Tierra del Fuego and southeast Brazil. Surprisingly, we have discovered that large subterranean tubers are produced in approximately one fourth of the populations surveyed. These usually arise from ventrally oriented branch initials on main stems, but may also develop from shoot apices. Often sporophytes and tubers are present on the same plant. In some populations, the mature tubers are ellipsoidal, 0.42-2.52 x 0.23-1.14 mm, but in others even at maturity the tubers are spheroidal, 0.40-1.52 mm in diameter. Populations with ellipsoidal forms are most common in southern Brazil, while those with the spheroidal forms are more widespread. SEM and paraffin sectioning techniques were used to study the structure and development of these tubers. In young tubers the apical cell is replaced by a flattened meristem; as the tubers mature, cells of the surrounding leaves and stem epidermis become thick-walled and the interior cells are packed with large starch grains. Germinating tubers were only rarely observed. Our findings suggest that tubers in Noteroclada function primarily in nutrient storage and only secondarily as asexual propagules.
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1 - Southern Illinois University, Department of Plant Biology, 1125 Lincoln Drive, Carbondale, Illinois, 62901-6509, USA
simple thalloid liverwort
Presentation Type: Poster
Location: Salon C, D & E - Gov Ballroom/Hilton
Date: Tuesday, August 16th, 2005
Time: 12:30 PM