Heavy metal toxicity: cadmium permeates through calcium channels and disturbs the plant water status

• Laetitia Perfus‐Barbeoch

• Nathalie Leonhardt

• Alain Vavasseur

• Cyrille Forestier

抄録

Because plant wilting has been described as a consequence of cadmium (Cd 2+ ) toxicity, we investigate Cd 2+ effects on plant water losses, gas exchanges and stomatal behaviour in Arabidopsis thaliana L. Effects of 1‐week Cd 2+ application in hydroponic condition (CdCl 2 10–100 µ m ) were analyzed. A 10‐µ m Cd 2+ concentration had no significant effect on the plant–water relationship and carbon assimilation. At higher Cd 2+ concentrations, a Cd 2+ ‐dependent decrease in leaf conductance and CO 2 uptake was observed despite the photosynthetic apparatus appeared not to be affected as probed by fluorescence measurements. In epidermal strip bioassays, nanomolar Cd 2+ concentrations reduced stomatal opening under light in A. thaliana, Vicia faba and Commelina communis . Application of 5 µ m ABA limited the root‐to‐shoot translocation of cadmium. However, the Cd 2+ ‐induced stomatal closure was likely ABA‐independent, since a 5‐day treatment with 50 µ m Cd 2+ did not affect the plant relative water content. Additionally, a similar Cd 2+ ‐induced stomatal closure was observed in the ABA insensitive mutant abi1‐1 . Interestingly, this mutant displayed a higher transpiration rate than the wild type but did not accumulate more Cd 2+ , arguing that Cd 2+ uptake is not dependent only on the transpiration flow. Application of putative calcium channels inhibitors suppressed the inhibitory effect of Cd 2+ in epidermal strip experiments, suggesting that Cd 2+ could enter the guard cell through calcium channels. Patch‐clamp studies with V. faba guard cell protoplasts showed that plasma membrane K + channels were insensitive to external Cd 2+ application whereas Ca 2+ channels were found permeable to Cd 2+ . In conclusion, we propose that Cd 2+ affects guard cell regulation in an ABA‐independent manner by entering the cytosol via Ca 2+ channels.

収録刊行物

• The Plant Journal

  The Plant Journal 32 (4), 539-548, 2002-11

  Wiley

キーワード

• Cell Biology
• Plant Science
• Genetics

詳細情報

• CRID: 1362544419061547648
• NII論文ID: 30014609047
• DOI: 10.1046/j.1365-313x.2002.01442.x
• ISSN: 1365313X
• ISSN: 09607412
• ISSN: http://id.crossref.org/issn/09607412
• Web Site: https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1046%2Fj.1365-313X.2002.01442.x
• Web Site: https://onlinelibrary.wiley.com/doi/pdf/10.1046/j.1365-313X.2002.01442.x
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