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Effects of Ca addition on the uptake, translocation, and distribution of Cd in Arabidopsis thaliana

Author:
  • Lihua Zeng
  • Ting Zhu
  • Ya Gao
  • Yutao Wang
  • Chanjuan Ning
  • Lars Olof Björn
  • Da Chen
  • Shaoshan Li
Publishing year: 2017-05-01
Language: English
Pages: 228-237
Publication/Series: Ecotoxicology and Environmental Safety
Volume: 139
Document type: Journal article
Publisher: Elsevier

Abstract english

Cadmium (Cd) pollution poses a risk to human health for its accumulation in soil and crops, but this can be alleviated by calcium (Ca) addition. However, its mechanism remains unclear yet. In this study, Arabidopsis thaliana was used to explore the alleviating effects of Ca on Cd toxicity and its specific function during uptake, upward-translocation, and distribution of Cd. Supplementing plants with 5 mM CaCl2 alleviated the intoxication symptoms caused by 50 μM CdCl2, such as smaller leaves, early bolting and root browning. Ca addition decreased uptake of Cd, possibly by reducing the physical adsorption of Cd since the root cell membrane was well maintained and lignin deposition was decreased as well, and by decreasing symplastic Cd transport. Expression of the genes involved (AtZIP2 and AtZIP4) was also decreased. In addition, Ca accumulated in the plant shoot to help facilitating the upward-translocation of Cd, with evidence of higher translocation factor and expression of genes that were involved in Ca transport (AtPCR1) and Cd xylem loading (AtHMA2 and AtHMA4). Dithizone-staining of Cd in leaves showed that in Cd+Ca-treated plants, Ca addition initially protected the leaf stomata by preventing Cd from entering guard cells, but with prolonged Cd treatment facilitated the Cd accumulation around trichomes and maybe its excretion. We conclude that Ca promotes the upward-translocation of Cd and changes its distribution in leaves. The results may have relevance for bioremediation.

Keywords

  • Environmental Sciences
  • Environmental Health and Occupational Health
  • Alleviating effect
  • Cd distribution
  • Cd toxicity
  • Cd uptake and translocation
  • Exogenous Ca

Other

Published
  • ISSN: 0147-6513
Lars Olof Björn
E-mail: lars_olof [dot] bjorn [at] biol [dot] lu [dot] se

Professor emeritus

Molecular Cell Biology

+46 46 222 72 53

B-A340

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