Recent Topics Posters
Meloche, Christopher G. , Vaughn, Kevin C. .
The adhesive shoot tendril of Brunnichia ovata (Polygonaceae).
The vining weed Brunnichia ovata climbs by means of axillary shoot tendrils. SEM, TEM and histochemical staining were used to study the anatomy and biochemistry of tendrils in this species. Tendrils attach to supports via twining and production of a polyphenolic adhesive. Both stem and leaf components of tendrils have epidermal cells with large quantities of vacuolar phenolic compounds and plastids highly enriched in polyphenol oxidase (PPO). In response to contact with a support, the epidermal cells become thin-walled and bulge producing a papillate surface. Epidermal cells subsequently rupture releasing an exudate that rapidly polymerizes and cross-links to form a sticky adhesive pad attaching the plant to the support. This is the first time PPO has been implicated in generating an adhesive in a climbing plant. Internally, the tendrils of B. ovata exhibit precocious development of vascular tissue. Even very young leaf tendrils contain inextensible xylem extending to the distal tip. Development of lignified xylem along the length of the tendril results in a tough, elastic attachment structure capable of supporting a rapidly expanding foliar shoot. Because adhesive tendrils are the mechanism whereby B. ovata to overtops and shades crop plants, these data serve to partially explain the aggressiveness of this troublesome vining weed.
1 - USDA-ARS, Southern Weed Science Research Unit, Stoneville, Mississippi, 38776, United States
Presentation Type: Poster
Location: Special Event Center (Cliff Lodge)
Date: Tuesday, August 3rd, 2004
Time: 12:30 PM