The emergence of grass root chemical ecology
- Natural Products Utilization Research Unit, Agricultural Research Service, U.S. Department of Agriculture, P.O. Box 8048, University, MS 38677
Allelopathy is defined by most scientists as the adverse effect of one plant species on another through production of phytotoxins (allelochemicals), although more expansive definitions have been formulated. Allelopathy is but one component of plant/plant interference, the other being competition for resources such as nutrients, light, and water. Allelopathy has been a recognized phenomenon for many years (1), but prominent ecologists have argued that allelopathy is seldom a significant component of interference (e.g., ref. 2). This point of view was bolstered by the lack of scientific rigor of much of the allelopathy research that attempted to explain allelopathy through the effects of known, weakly phytotoxic, easy-to-quantify phytochemicals such as ferulic acid. More recent studies using bioassay-guided isolation and subsequent structure determination of potent, root-exuded phytotoxins built strong evidence for allelopathy, especially in grass species (reviewed in refs. 3–5, and see Table 1). The article by Bertin et al. (6) in this issue of PNAS adds significantly to this growing body of supportive literature.
- In this window
- In a new window
Highly phytotoxic root-secreted allelochemicals by grasses (5, 6)
The work provides clear evidence of a novel, root-exuded allelochemical produced by an allelopathic grass, a variety of a Festuca rubra subspecies. It establishes that m-tyrosine is a highly active allelochemical causing most, if not all, of the effects of …
*E-mail: sduke{at}olemiss.edu
