Biphasic response to elevated levels of NaCl in Nicotiana occidentalis subspecies obliqua Burbidge

Published Date
Plant Science
July 2003, Vol.165(1):159–165, doi:10.1016/S0168-9452(03)00154-7

• Author 

• Toshiyuki Komori ^,
• Shigehiro Yamada
• Patricia N. Myers
• Hidemasa Imaseki

• Plant Breeding and Genetics Research Laboratory, Japan Tobacco Inc., 700 Higashibara, Toyoda, Iwata, Shizuoka 438-0802, Japan

Received 14 November 2002. Revised 18 March 2003. Accepted 19 March 2003. Available online 30 April 2003. 

Abstract

The seedling growth response of N. occidentalis subspecies obliqua Burbidge to elevated levels of NaCl was studied under various conditions with respect to light/dark cycle and temperature. When cultured at 28 °C under continuous light, the seedlings showed a unique biphasic response to NaCl; the seedlings died in the presence of 75 mM NaCl, while they survived in the presence of 150 mM NaCl. The results of Na⁺ and K⁺ accumulation in leaves suggested that this biphasic response was not due to the disruption of ion homeostasis under 75 mM NaCl. A similar phenomenon was observed when NaCl was replaced with KCl. Moreover, seedlings survived in the coexistence of 75 mM KCl or KNO₃ even under 75 mM NaCl. These results implied that the seedling response may be determined by the differential expression of salt-inducible gene(s) rather than specific ion toxicity. The biphasic response may be useful for understanding the salt tolerance mechanisms and for isolating the involved gene(s).

Keywords

Biphasic response

Nicotiana occidentalis

Salinity stress

Salt tolerance

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• * 
  Corresponding author. Tel.: +81-538-32-8592; fax: +81-538-33-6046. Present address: Plant Innovation Center, Japan Tobacco Inc., 700 Higashibara, Toyoda, Iwata, Shizuoka, 438-0802, Japan

Copyright © 2003 Elsevier Science Ireland Ltd. All rights reserved.

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