PARENT SESSION
Organized Oral Session 16: Allelopathy: Biochemical interactions among plants affecting community structure, exotic invasions and evolutionary theory
Organizer(s): A Mallik and R Callaway
Tuesday, August 9, 8:00 AM - 11:30 AM, Meeting Room 511 C, Level 5, Palais des congrès de Montréal
The ecology and chemistry of novel allelochemicals in graminaceous root exudates and their potential utilization as bioherbicides or weed suppressive agents.
Weston, Leslie*,1, Bertin, Cecile1, Yang, Xiaohan1, Scheffler, Brian2, 1 Cornell University, Ithaca, NY, USA2 USDA ARS, Stoneville, MS, USA
ABSTRACT- Roots of many weed and crop species contribute mixtures of biologically active chemicals into the environment through their root exudates. Root exudates are known to influence growth and establishment of crop and weed species and are released by living roots or root hairs. Many perennial plants have extensive root systems which can produce prolific amounts of exudates and allelochemicals over time. We have isolated and identified a number of biologically active novel secondary products from the root exudates of graminaceous species, including Sorghum spp., Festuca spp. and Secale spp. Root exudation in these species can be modified by physical factors such as oxygen availability, ethylene production and drought stress or water availability. The production of long chain hydroquinones by Sorghum spp. and amino acid analogues by Festuca spp. are examples of crop species which effectively suppress the growth of germinating weed seeds and potentially influence other rhizospheric interactions by production of biologically active plant growth inhibitors. The mode of action of these natural products is similar to that of synthetic soil-applied herbicides including the phenyl ureas and triazines (photosystem II inhibitors) and the dinitroanilines (mitotic disrupters). We have focused most recently on localization of site of production of these bioactive exudates and isolation and expression of key genes involved in their biosynthesis and release from living root cell.
Key words: allelopathy, root, exudate, suppression