Plant and Soil

, Volume 203, Issue 1, pp 119–126 | Cite as

Phytochelatins as biomarkers for heavy metal stress in maize (Zea mays L.) and wheat (Triticum aestivum L.): combined effects of copper and cadmium

  • W.G. Keltjens
  • M.L. van Beusichem


Heavy metal contaminated soils often show increased levels of more than one metal, e.g. copper (Cu), cadmium (Cd), zinc (Zn), lead (Pb) or nickel (Ni). In case such soils are used for crop production, prediction of yield reduction or quality decline due to heavy metals in the soil is inadequate when based only on chemical soil analysis. The use of biomarkers such as phytochelatins (PC), non-protein thiols specifically induced in plants upon exposure to heavy metals, may be an additional tool or diagnostic criterion in heavy metal research and in practice. In the present work, Cu and Cd uptake and induction of PC synthesis are studied with hydroponically grown maize and wheat plants exposed to mixtures of the two metals. We observed a close positive relationship between the concentrations of Cd and PC in the plant shoot material. A decreased shoot concentration of Cd after addition of Cu, due to metal competition at common root absorption sites, coincided with lower shoot PC levels. Also differences in metal uptake and xylary metal transport among the two plant species were reflected in corresponding differences in PC concentration. The observed direct relationship between shoot PC concentration and the degree of metal-induced growth inhibition makes the use of PC promising for the purpose tested for.

biomarker cadmium copper heavy metal PC PC-SH phytochelatin stress toxicity Triticum aestivum Zea mays 


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Copyright information

© Kluwer Academic Publishers 1998

Authors and Affiliations

  • W.G. Keltjens
    • 1
  • M.L. van Beusichem
    • 1
  1. 1.Department of Environmental Sciences; Sub-department of Soil Science and Plant NutritionWageningen Agricultural UniversityWageningenThe Netherlands

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