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Allelopathic Potential of Fine Leaf Fescue: Isolation and Identification of a key Phytotoxin.

Cecile Bertin1, Frank C. Schroeder2 and Leslie A. Weston1

1Department of Horticulture, 134A Plant Science, Cornell University, Ithaca NY 14853
2Department of Chemistry and Chemical Biology, Baker Laboratory, Cornell University, Ithaca, NY 4853-130

law20@cornell.edu

Abstract

There is a recent movement to eliminate or reduce the use of synthetic pesticides in turf management in many communities, based on increasing environmental and health concerns. Therefore, the turf industry is seeking alternative weed management strategies. Recent approaches involving allelopathy have resulted in the development of successful “green strategies” for weed management. Through a variety of field and laboratory experiments, our research has shown that fine leaf fescues possess significant allelopathic potential. Our analysis using activity- guided fractionation of fescue root exudates showed that weed suppressive ability is associated with an amino acid analogue, m-tyrosine, which accounts for most of the weed suppressive activity observed within extracted fine leaf fescue root exudates. M-tyrosine, a relatively simple structure and currently available synthetically, could have great value as a potential bioherbicide. At this time, we have performed experiments in the laboratory that show that m-tyrosine is a selective inhibitor of turf weed growth, suppressing radicle elongation by inhibiting cell division. This compound is also active in amended soil at low concentrations (I50=17 ÁM) In addition, environmental conditions which mimic competition-induced moisture stress, impact production of m-tyrosine and root exudation in fine leaf fescues. Reduced moisture availability resulted in a 2 to 3-fold increase in production of m-tyrosine. Here, we report the effect of environmental stresses on m-tyrosine production as well as the impact of this amino acid analog upon growth of a variety of organisms.

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