Dose-Response - a Challenge for Allelopathy?

Publication Type

Journal contribution

Authors

Belz, R. G. and Duke, S. O. and Hurle, K.

Year of publication

2005

Published in

Journal of Non-Linearity in Biology, Toxicology and Medicine

Band/Volume

3/2

ISBN / ISSN / eISSN

1540-1421

Nonlinear dose-response relationships occur across a broad range of research fields, and are a well-established toll to describe the basic mechanisms of phytotoxicity. The responses of living plants to allelochemicals as biosynthesized phytotoxins, relate as well to nonlinearity and thus, allelopathic interactions can be adequately quantified by nonlinear statistical modeling. By means of several bioassays, the concept of nonlinearity is applied to study assorted aspects of allelopathic interactions and their analysis by nonlinear regression models. The presented dose-response applications measure and compare the responses produced by synthetic allelochemicals (DIBOA, BOA, MBOA, scopoletin), involved in allelopathic interactions of grain crops, to demonstrate how some general principles of dose responses also relate to allelopathy. Hereupon, dose-response applications with living grain crops demonstrate the validity of these general principles for the phytotoxicity of allelochemicals produced and released by living plants (Avena sativa, Hordeum vulgare, Secale cereale, Triticum spp.), and reveal the use of such experiments for initial considerations about basic principles of allelopathic interactions. Results confirm that nonlienarity applies to allelopathy, and the study of allelopathic effects in dose-response experiments allows for new and challenging insights into allelopathic interactions. Interpretive Summary: The effects of various parameters on the toxicity of several natural compounds from wheat, oats, rye, and barley on other plants is described. Detailed dose-response experiments were used to characterize the effects of these parameters on the relationships between dose of the phytotoxins and their effects on a variety of physiological and growth parameters. The experiments were done with pure phytotoxins, as well as by allowing the producing plants to provide the phytotoxin in different amounts to the target plant species. This work demonstrates the use of such analyses in determining differences in mode of action of different phytotoxins, as well as in providing new and challenging insights into allelopathic interactions. Keywords: hormesis, benzoxazinoids, log-logistic model, scopoletin