Planta

, Volume 213, Issue 1, pp 45–50

Detoxification of cadmium in tobacco plants: formation and active excretion of crystals containing cadmium and calcium through trichomes

  • Y.-E. Choi
  • E. Harada
  • M. Wada
  • H. Tsuboi
  • Y. Morita
  • T. Kusano
  • H. Sano

DOI: 10.1007/s004250000487

Cite this article as:
Choi, YE., Harada, E., Wada, M. et al. Planta (2001) 213: 45. doi:10.1007/s004250000487

Abstract.

In tobacco (Nicotiana tabacum L.), long and short trichomes can be distinguished morphologically. The established function of long trichomes is to exude a sticky gum containing diterpenes, whereas that of short trichomes is not known. When tobacco seedlings were exposed to toxic levels of cadmium (Cd), growth was retarded, but trichome number was increased up to 2-fold in comparison with untreated samples. Observation by variable-pressure scanning electron microscopy (VP-SEM) indicated that large crystals of 150 μm in size were formed on head cells of both short and long trichomes. An energy-dispersive X-ray analysis system fitted with VP-SEM revealed the crystals to contain amounts of Cd and calcium (Ca) at much higher concentrations than in the head cells themselves. Transmission electron microscopy demonstrated crystal formation in amorphous osmiophilic deposits in vacuoles. When seedlings were treated with Cd in the presence of Ca, tolerance was increased in proportion to the increase in Ca concentration. These results indicate that tobacco plants actively exclude toxic Cd by forming and excreting Cd/Ca-containing crystals through the head cells of trichomes.

Key words: Cadmium detoxification Calcium excretion Heavy metal Nicotiana (cadmium) Trichome 

Copyright information

© Springer-Verlag Berlin Heidelberg 2001

Authors and Affiliations

  • Y.-E. Choi
    • 1
  • E. Harada
    • 1
  • M. Wada
    • 2
  • H. Tsuboi
    • 2
  • Y. Morita
    • 3
  • T. Kusano
    • 1
  • H. Sano
    • 1
  1. 1. Research and Education Center for Genetic Information, Nara Institute of Science and Technology, Ikoma, Nara 630-0101, JapanJP
  2. 2. Hitachi Science Systems, Ltd., Hitachinaka, Ibaraki, 312-8504, JapanJP
  3. 3. Horiba Ltd., Kyoto, 601-8305, JapanJP

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