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Research article2005Peer reviewed

Uptake of sodium in protoplasts of salt-sensitive and salt-tolerant cultivars of rice, Oryza sativa L. determined by the fluorescent dye SBFI

Kader, MA; Lindberg, S

Abstract

In this study, the uptake of Na+ into the cytosol of rice (Oryza sativa L. cvs Pokkali and BRRI Dhan29) protoplasts was measured using the acetoxy methyl ester of the fluorescent sodium-binding benzofuran isopthalate, SBFI-AM, and fluorescence microscopy. By means of inhibitor analyses the mechanisms for uptake and sequestration of Na+ in the salt-sensitive indica rice cv. BRRI Dhan29 and in the salt-tolerant indica rice cv. Pokkali were detected. Less Na+ was taken up into the cytosol of Pokkali than into BRRI Dhan29. The results indicate that K+-selective channels do not contribute to the Na+ uptake in Pokkali, whereas they are the major pathways for Na+ uptake in BRRI Dhan29 along with non-selective cation channels. However, non-selective cation channels seem to be the main pathways for Na+ uptake in Pokkali. Protoplasts from Pokkali leaves took up Na+ only transiently in the presence of extracellular Na+ at 5–100 mM. Therefore, it is likely that the protoplasts have a mechanism for fast extrusion of Na+ out of the cytoplasm. Experiments with protoplasts pretreated with NH4NO3 and NH4VO3 suggest that the salt-tolerant Pokkali extrudes Na+ mainly into the vacuole. After cultivation of both cultivars in the presence of 10 or 50 mM NaCl for 72 h, the isolated protoplasts from Pokkali took up less Na+ than the control protoplasts. The results suggest that the salt-tolerance in Pokkali depends on reduced uptake through K+-selective channels and a fast extrusion of Na+ into the vacuoles

Keywords

Benzofuran isophthalate; compartmentalization; fluorescence ratio microscopy; influx; rice; salt stress; sodium uptake

Published in

Journal of Experimental Botany
2005, volume: 56, number: 422, pages: 3149-3158

SLU Authors

UKÄ Subject classification

Agricultural Science

Publication identifier

  • DOI: https://doi.org/10.1093/jxb/eri312

Permanent link to this page (URI)

https://res.slu.se/id/publ/8399