Developmental and Structural Section
Meloche, Christopher G. , Vaughn, Kevin C. .
Gelatinous fibers cause coiling in redvine tendrils.
TENDRILS are one of the plant world’s most fascinating organs, allowing vining plants to ascend any surrounding object with a minimum of tissue involved in the process. However, the mechanisms by which these tendrils are able to modify their shapes and twine about supports are not known. In our studies of redvine tendrils, we discovered that the ability of the tendril to coil occurs after elongation and coincidently with the de novo appearance of a band of fiber cells between the epidermis and vascular tissue. These fibers are unique compositionally and organizationally compared to many other plant fibers and are most similar to the gelatinous fibers found in tree branches that require righting. The fiber cell wall consists of a primary wall/middle lamellae complex, two thick S layers, and a gelatinous layer immediately adjacent to the plasmalemma. Compositionally, the S layers are enriched in cellulose, callose, xyloglucan and lignin and impoverished in pectins of all types whereas the gelatinous layer has relatively little lignin and abundant rhamnogalacturtons compared with the S layers. The compositional differences between the G and S layers allows for a differential swelling of the layers, giving rise to a tension that causes a twisting in the fiber cell and consequently in the organ as a whole. Variations in the extent of lignification (higher towards the touched side) of the primary wall and S layers would allow for subtle changes in the extent of twisting of a given fiber cell. Taken to the organ level, this allows tendrils the structural flexibility to twine about objects of many different sizes and morphologies.
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1 - USDA-ARS, Southern Weed Science Research Unit, Stoneville, Mississippi, 38776, USA
Presentation Type: Poster:Posters for Sections
Location: Auditorium/Bell Memorial Union
Date: Tuesday, August 1st, 2006
Time: 12:30 PM