Plant and Soil

, Volume 178, Issue 1, pp 83–93

Phytotoxic effects of the high molecular weight fraction of an aqueous leaf litter extract on barley root development

  • I. Brunner
  • J. Luster
  • M. Ochs
  • P. Blaser
Research Article

DOI: 10.1007/BF00011166

Cite this article as:
Brunner, I., Luster, J., Ochs, M. et al. Plant Soil (1996) 178: 83. doi:10.1007/BF00011166


The root development of barley seedlings grown for one week in an aerated nutrient solution was studied in the presence of dissolved organic matter from an aqueous chestnut leaf litter extract. In particular, the different effects of low and high molecular weight fractions (small molecules: molecular weight <1000; large molecules: >10,000) of the leaf litter extract were examined. In the presence of large molecules root growth was inhibited, an irregular root tip morphology was observed, and Ca and Mg concentrations in the shoots were lower than in control plants. These phytotoxic effects were not caused by the formation of an impermeable layer of large molecules on the root surfaces that lower accessibility for nutrient cations as inferred from voltammetric experiments. A germination assay using spruce seeds, however, indicated allelochemical effects of large molecules, which exhibit a higher aromaticity than the small molecules as indicated by spectroscopic characterisation. In the growth experiments with small molecules, no influence on the root development of barley was evident, but an increase of Ca and Mg in the shoots was detected. During these growth experiments, a large amount of the small molecules, mainly simple phenols and amino acids, disappeared from the nutrient solution. The loss of small molecules was most likely the effect of mineralisation.

Key words

adsorption behaviour dissolved organic matter leaf litter extract molecular weight fractions phytotoxicity root development 



dissolved organic carbon


dissolved organic matter


leaf litter extract


molecular weight


hanging mercury drop electrode

Copyright information

© Kluwer Academic Publishers 1996

Authors and Affiliations

  • I. Brunner
    • 1
  • J. Luster
    • 1
  • M. Ochs
    • 2
  • P. Blaser
    • 1
  1. 1.Snow and Landscape Research (WSL)Swiss Federal Institute for ForestBirmensdorfSwitzerland
  2. 2.Swiss Federal Institute for Environmental Science and Technology (EAWAG)DübendorfSwitzerland